The cost of a washing machine is 40% less than the cost of a TV. If the cost of the washing machine increases by 73% and that of the TV decreases by 67%, then what is the percentage change in the total cost of 5 washing machines and 2 TVs?

Correct answer: Increase by 17%. Let TV cost be T, so washing machine cost is 0.6T. Old total = 5(0.6T) + 2T = 5T. New total = 5(1.73 x 0.6T) + 2(0.33T) = 5.85T, which is 17% more than 5T.

If 30 workers earn Rs. 4,000 in 3 days, how much will 54 workers earn in 6 days?

Correct answer: Rs. 14,400. Earnings are proportional to workers and days. Required earning = 4000 x (54 / 30) x (6 / 3) = Rs. 14,400.

The sum of two numbers is 49, and their LCM is 70. The two numbers are:

Correct answer: 14, 35. The pair 14 and 35 has sum 49 and LCM 70.

The ratio of the heights of a right circular cone and a right circular cylinder is 8 : 3, and the ratio of the radii of their bases is 9 : 2. If the volume of the cylinder is 792 cm3, then the volume of the cone is:

Correct answer: 14256. Cone/cylinder volume ratio = (1/3) x (9/2)^2 x (8/3) = 18. Therefore cone volume = 18 x 792 = 14256 cm3.

During a Big Billion Day sale, a flagship mobile phone was available at a 20% discount on an e-commerce platform. Customers purchasing for the first time on the platform received an additional 10% cashback on the billing amount. Suraj, being a first-time user, purchased the mobile phone for Rs. 36,000. Find the original marked price of the mobile phone.

Correct answer: 50,000. After 20% discount and 10% cashback on the billed amount, effective payment = 0.9 x 0.8 x marked price = 0.72M. Since 0.72M = 36,000, M = 50,000.

Sujit is three times as old as his son, and his daughter is 3 years younger than the son. If the sum of the ages of these three people 3 years ago was 63 years, then Sujit's present age is:

Correct answer: 45. Let son's present age be x. Then Sujit = 3x and daughter = x - 3. Three years ago their sum was (3x - 3) + (x - 3) + (x - 6) = 63, so 5x = 75 and Sujit = 45.

A class of 75 students took a Physics test. 22 students had an average score of 90. The other students had an average score of 70. What is the average score, rounded off to one decimal place, of the whole class?

Correct answer: 75.9. Overall average = (22 x 90 + 53 x 70) / 75 = 5690 / 75 = 75.866..., which rounds to 75.9.

X varies inversely as Y and Y varies inversely as Z. In a particular case, X = 1/5 and the remaining condition is as shown in the official question image. Find the required value.

Correct answer: 16. Since X varies inversely as Y and Y varies inversely as Z, X varies directly as Z. Applying the given case from the official question gives the required value as 16.

A scooter travelling at two-third of its actual speed covers 66 km in 1 hr 6 mins. Find the actual speed of the scooter.

Correct answer: 90 km/hr. 1 hr 6 mins = 1.1 hours. Speed during the trip = 66 / 1.1 = 60 km/hr. This is two-third of actual speed, so actual speed = 60 x 3/2 = 90 km/hr.

During a sale, 44% of the goods are sold at a profit of 28%, 25% of the remaining goods are sold at a profit of 48%, and the rest are sold at a loss of 13%. All items have the same cost price. If there is an overall profit of x%, then what is the value of x?

Correct answer: 13.58. For 100 equal-cost items: profit = 44 x 28% + 14 x 48% - 42 x 13% = 12.32 + 6.72 - 5.46 = 13.58%.

The LCM of the numbers 18, 78 and 49 is:

Correct answer: 11466. 18 = 2 x 3^2, 78 = 2 x 3 x 13, and 49 = 7^2. LCM = 2 x 3^2 x 13 x 7^2 = 11466.

Mohan has two grandsons, Pramod and Ashish. 14-year-old Pramod gets some money from Mohan's wealth, and 15-year-old Ashish gets the rest of the money. But Pramod and Ashish will get the money only when they turn 23 years old. Till then, the money is in a bank getting interest at the rate of 8% per annum, compounded annually. When both turn 23, they receive the same amount. How much money does Mohan give Ashish initially, if the total money with Mohan was Rs. 24,700?

Correct answer: 12,825. Ashish's money compounds for 8 years and Pramod's for 9 years. Equal maturity gives Ashish's initial share = 1.08 times Pramod's share, so Ashish receives 24700 x 1.08 / 2.08 = Rs. 12,825.

Select the pair which follows the same pattern as that followed by the two sets of pairs given below. Both pairs follow the same pattern. QPI : PMJ; DTN : CQO

Correct answer: PMS : OJT. The same letter-position shifts used in QPI -> PMJ and DTN -> CQO are followed by PMS -> OJT.

Each of the digits in the number 5976248 is arranged in descending order from left to right. The positions of how many digits will remain unchanged as compared to those in the original number?

Correct answer: Three. Descending arrangement is 9876542. Comparing with 5976248, the digits at positions 3, 4, and 6 remain unchanged.

Based on the English alphabetical order, three of the following four letter-cluster pairs are alike in a certain way and thus form a group. Which letter-cluster pair DOES NOT belong to that group? Note: The odd one out is not based on the number of consonants/vowels or their position in the letter-cluster.

Correct answer: TU-VX. TU-VX does not follow the same alphabetical shift pattern as the other three pairs.

Each vowel in the word MINDFUL is changed to the letter immediately following it in the English alphabetical order and each consonant is changed to the letter immediately preceding it in the English alphabetical order. How many vowels are there in the group of letters thus formed?

Correct answer: One. MINDFUL becomes LJMCEVK. Only E is a vowel, so there is one vowel.

Seven people F, G, H, I, V, W, and X are sitting in a straight line facing north. Only two people sit between G and W. Only X sits to the right of H. Only one person sits between W and H. I sits at some place to the right of F and at some place to the left of V. How many people sit between V and F?

Correct answer: Two. Arranging the people according to all the given conditions leaves two people between V and F.

LQ 22 is related to HN 5 in a certain way. In the same way, KR 19 is related to GO 2. To which of the following is GH 16 related, following the same logic?

Correct answer: CE -1. Following the same letter and number shifts as in LQ 22 -> HN 5 and KR 19 -> GO 2, GH 16 maps to CE -1.

Refer to the following letter and symbol series and answer the question that follows. Counting is to be done from left to right only. (Left) N Z \ D J G % W C U B F E Q \ G V # C S (Right). How many such symbols are there each of which is immediately preceded by a letter and also immediately followed by a symbol?

Correct answer: None. In the given sequence, no symbol satisfies both conditions simultaneously.

Refer to the given letter series and answer the question that follows. Counting is to be done from left to right only. (Left) C Y B H I N M K O P G D A W E D C T U I T (Right). How many such consonants are there, each of which is immediately preceded by a vowel and also immediately followed by a vowel?

Correct answer: One. Only one consonant in the series is immediately preceded by a vowel and immediately followed by a vowel.

What will come in place of the question mark (?) in the following equation, if '+' and '-' are interchanged and 'x' and '/' are interchanged? 4 / 2 + 6 x 3 - 4 = ? + 16

Correct answer: 26. After interchanging the signs, the equation becomes 4 x 2 - 6 / 3 + 4 = ? - 16. Thus 10 = ? - 16, so ? = 26.

In a certain code language, 'SONG' is coded as '6423' and 'ONES' is coded as '2648'. How is 'E' coded in that language?

Correct answer: 8. E appears in ONES, and the code shown for E is 8.

Seven boxes, Q, R, S, T, G, H and I, are kept one over the other, but not necessarily in the same order. Only H is kept above I. Only T is kept between S and Q. Only G is kept below S. How many boxes are kept between R and G?

Correct answer: Three. Using the vertical-order conditions, there are three boxes between R and G.

What should come in place of ? in the given series based on the English alphabetical order? DZD HWL ITN PQS ?

Correct answer: TNX. The letter positions follow the series pattern ending with TNX.

Based on the English alphabetical order, three of the following four letter-clusters are alike in a certain way and thus form a group. Which letter-cluster DOES NOT belong to that group? Note: The odd one out is not based on the number of consonants/vowels or their position in the letter-cluster.

Correct answer: LRM. LRM does not follow the same letter-position pattern as the other three clusters.

The transfer function of a network is given by H(s) = (s + 2) / ((s + 4)(s + 6)). The poles are:

Correct answer: Z = -2, P1 = -4, P2 = -6. The zero comes from the numerator s + 2 = 0, so z = -2. The poles come from s + 4 = 0 and s + 6 = 0, so the poles are -4 and -6.

A metal oxide semiconductor field effect transistor (MOSFET) is used in a self-biasing circuit with a drain resistor (RD) and a source resistor (RS). If the value RS is increased, which of the following options is an immediate effect on the quiescent drain current (IDQ) and the quiescent gate-source voltage (VGSQ)?

Correct answer: IDQ decreases, and VGSQ becomes more negative.. Increasing the source resistance increases source degeneration. The source voltage rises for a given current, making VGS more negative and reducing the quiescent drain current.

Which of the following statements correctly describes the s-domain shifting property?

Correct answer: Multiplying the signal by e^at in the time domain shifts the s-domain X(s) to X(s - a).. The Laplace transform property is L{x(t)e^(at)} = X(s - a).

A slab of perfect dielectric (epsilon r = 2) is adjacent to air. Inside the slab, the normal electric field is sinusoidal: Ed(t) = Eo cos(omega t) an, with Eo = 300 V/m. Assume mu r = 1, no free surface charge at the interface, and the field is normal to the surface. Which option correctly gives the amplitudes of the displacement current density Jd in the dielectric and in air, respectively?

Correct answer: Equal and non-zero (same value in both media). With no free surface charge, the normal displacement field is continuous across the boundary. Therefore the displacement current density amplitudes are equal and non-zero.

A single-stage common-emitter amplifier is modelled with h-parameters hie = 1000 ohm, hfe = 50, and hre is negligible. The collector resistor is RC = 4.7 kohm and the amplifier drives a load RL = 10 kohm connected at the collector. Neglect hoe effects. The approximate midband voltage gain Av = Vo / Vi is:

Correct answer: -160. The effective collector load is RC || RL = 4.7k || 10k about 3.2k. The gain is approximately -hfe(RC || RL)/hie = -50 x 3.2k/1k about -160.

What is the result of a 4-bit ring counter which performs left shifting the 4-bit number 0100 three times to the left?

Correct answer: 0010. For a ring shift, 0100 left-shifts to 1000, then 0001, then 0010.

Choose the correct statement. S1: The intermediate frequency for AM radio in superheterodyne (SHD) receiver is 455 kHz. S2: The first section in a superheterodyne (SHD) receiver is frequency converter. S3: The purpose of RF section in a superheterodyne (SHD) receiver is to pick up the desired station.

Correct answer: S1 and S3 only. The standard AM IF is 455 kHz, and the RF section selects the desired station. The first section is normally the RF/tuner stage, not the converter.

When a control system is represented as a Block Diagram (BD) or a Signal Flow Graph (SFG), both can show feedback and signal paths. Which statement is always true about the relation between these two forms?

Correct answer: If a Block Diagram has no feedback loops, then its Signal Flow Graph will also have no loops, and Delta = 1 in Mason's formula.. A feedforward-only block diagram maps to a signal-flow graph without loops. In Mason's gain formula, with no loops present, Delta is 1.

Study the given circuit and answer the question that follows. The circuit is a diode clipper with an AC input source Vi, a series diode D1 in the top branch, and a load resistor R connected across the output. Which statements are correct? S1: It is a series positive clipper circuit. S2: For the positive input voltage, output is clipped off. S3: Output will be negative when the diode is forward biased.

Correct answer: S1, S2 and S3. The diode orientation gives a series positive clipper, so the positive half cycle is clipped and output appears for the opposite polarity when the diode conducts.

The small signal equivalent of a Zener diode in reverse breakdown region is represented by:

Correct answer: Series combination of a DC voltage source and small dynamic resistance. In breakdown, a Zener diode is modeled as an approximately constant voltage source in series with its small dynamic resistance.

Which of the following is the key characteristic of a Field-Programmable Gate Array (FPGA) that distinguishes it from a Complex Programmable Logic Device (CPLD) in terms of architecture?

Correct answer: FPGAs use a hierarchy of configurable logic blocks and programmable routing, whereas CPLDs use a single, large programmable AND-OR plane.. FPGAs are built from configurable logic blocks with routing resources. CPLDs are commonly organized around macrocells and programmable AND-OR logic planes.

Two perfect dielectric media are separated by a charge-free planar boundary. Their relative permittivities are epsilon r1 = 6 and epsilon r2 = 2. In medium 1, the electric field at point P has magnitude E1 = 100 V/m and makes an angle alpha1 = 60 degrees with the normal to the boundary. Under electrostatic conditions, the angle alpha2 in medium 2 and the magnitude E2 are:

Correct answer: alpha2 = 30 degrees, |E2| = 100 sqrt(3) V/m. Tangential E is continuous and normal D is continuous. Applying the dielectric boundary conditions gives alpha2 = 30 degrees and E2 = 100 sqrt(3) V/m.

Design a pure parallel RLC resonant circuit having the following parameters: k = 2000 ohm equivalent parallel resistance, Q = 10 quality factor, omega0 = 5000 rad/s resonant angular frequency. Determine the values of inductance L and capacitance C of the circuit.

Correct answer: L = 40 mH, C = 1 uF. For a parallel resonant circuit, Q = R/(omega0 L), giving L = 2000/(10 x 5000) = 0.04 H. Then C = 1/(omega0^2 L) = 1 uF.

A silicon photodiode has a responsivity of 0.6 A/W at a certain wavelength. If the incident optical power is 2 milliwatts, then what is the photocurrent generated?

Correct answer: 1.2 mA. Photocurrent = responsivity x optical power = 0.6 x 2 mW = 1.2 mA.

A semi-infinite transmission line supports only a forward-traveling wave. V(z) = V+ e^(-gamma z), I(z) = (V+ / Z0)e^(-gamma z). The line has Z0 = 25 angle 0 degrees ohm and propagation constant gamma = (ln 2)/5 + j(pi/15) per meter. If the input voltage at z = 0 is V(0) = 50 angle 0 degrees V, find the current at z = 5 m.

Correct answer: 1 angle -60 degrees A. At z = 0, I(0) = 50/25 = 2 A. At z = 5 m, e^(-alpha z) = e^(-ln2) = 1/2 and the phase shift is -pi/3 = -60 degrees, so I = 1 angle -60 degrees A.

Which of the following options is correct in the context of the practical diode model?

Correct answer: It has fixed voltage drop when conducting.. The practical diode model includes a threshold or cut-in voltage, so a conducting diode is represented with an approximately fixed forward voltage drop.

The transfer function of a system is (5s^2 + 3s + 1) / (s^3 + 6s^2 + 11s + 6). Which of the following is the order of this system?

Correct answer: Third order. The order of a transfer-function system is the highest power of s in the denominator, which is 3.

If x1[n] X1(z) and x2[n] X2(z), then for y[n] = 3x1[n] - 2x2[n], the Z-transform is:

Correct answer: Y(z) = 3X1(z) - 2X2(z). By linearity of the Z-transform, constants carry through and sums/differences transform term by term.

The system has an impulse response defined by h(t) = sin(5t). Which of the following statements correctly describes the system?

Correct answer: The system is non-causal because h(t) is non-zero for t < 0.. For an LTI system to be causal, h(t) must be zero for t < 0. Since sin(5t) exists and is generally non-zero for negative time, the system is non-causal.

An EM wave of frequency f propagates in a non-magnetic medium (mu r = 1). The medium parameters are chosen such that sigma = omega epsilon (that is, sigma/(omega epsilon) = 1), where omega = 2 pi f and epsilon = epsilon0 epsilon r. What is the phase difference between the electric field E and the magnetic field H? Assume usual phasor convention.

Correct answer: 22.5 degrees. For sigma/(omega epsilon) = 1, the intrinsic impedance has phase angle 0.5 tan^-1(1) = 22.5 degrees, giving the E-H phase difference.

A series R-L-C circuit is excited by a sinusoidal source with frequency omega below its resonant frequency omega0. What is the nature of the circuit and the phase relationship between the supply voltage and the current?

Correct answer: Capacitive circuit; current leads the voltage. Below resonance, capacitive reactance exceeds inductive reactance in a series RLC circuit, so the circuit behaves capacitively and current leads voltage.

BEL ECE PYQ

BEL Probationary Engineer (ECE) Question Paper December 2025 with Solutions

Q: What is the difficulty level of BEL PE 2025?

The BEL PE ECE 2025 paper is best treated as moderate to difficult, with a mix of technical ECE, aptitude and reasoning questions.

Q: How many questions were asked in BEL PE 2025?

This BEL Probationary Engineer ECE 2025 paper contains 125 questions for practice with solutions and answer explanations.

Q: Is BEL PE suitable for ECE students?

Yes. BEL Probationary Engineer Electronics/ECE papers strongly overlap with core ECE subjects such as networks, analog, digital, control, communication, signals and electromagnetic theory.

Q: Which topics are most important for BEL PE?

Important BEL PE ECE areas include Analog Electronics, Communication Systems, Network Analysis, Control Systems, along with reasoning and aptitude practice.

Q: Where can I practice BEL previous year papers?

You can practice BEL previous year papers on ECE Exam Guide using the BEL paper hub, solved paper pages and BEL practice section.

Practice the BEL Probationary Engineer ECE December 2025 paper with detailed solutions, answer explanations, topic-wise analysis and exam-pattern focused revision.

Open QuestionsPractice Online

BEL ECE Details

125

Questions

100%

Solutions

Sections

119

Topics

Exam Analysis

BEL Probationary Engineer ECE 2025 Exam Analysis

Exam Date

December 2025

Total Questions

125

Difficulty Level

Moderate to Difficult

Technical Questions

100

Aptitude Questions

Reasoning Questions

The BEL Probationary Engineer ECE 2025 paper was moderate to difficult. The strongest technical weightage appears in Analog Electronics, Communication Systems, Network Analysis, Control Systems, Signals & Systems, so revision should prioritize formulas, circuit concepts, control-system plots, modulation basics and digital logic.

Topic-Wise Weightage

Topic-Wise Question Distribution

Subject	Questions
Network Analysis	11
Control Systems	11
Analog Electronics	17
Digital Electronics	7
Communication Systems	15
Signals & Systems	8
Electromagnetic Theory	6

High-Yield Revision

Most Important Topics Asked

Thevenin Theorem Norton Theorem BJT MOSFET Op-Amp Root Locus Bode Plot Modulation Sampling Digital Logic

Learn Related Topics

Subject navigation for BEL ECE

Network Analysis Control Systems Analog Electronics Digital Electronics Communication Systems Signals & Systems Electromagnetic Theory

Solved Questions

Interactive BEL ECE solutions

Loading embedded paper viewer...

Related BEL Papers

Continue year-wise BEL practice

BEL May 2025 Paper

Open solved paper and analysis

BEL 2024 Paper

Open solved paper and analysis

BEL December 2023 Paper

Open solved paper and analysis

BEL Preparation Cluster

Explore BEL resources

BEL Hub BEL Syllabus BEL Mock Tests BEL Previous Papers Topic Wise Questions BEL Important Topics

BEL PE FAQ

Frequently asked questions

What is the difficulty level of BEL PE 2025?

The BEL PE ECE 2025 paper is best treated as moderate to difficult, with a mix of technical ECE, aptitude and reasoning questions.

How many questions were asked in BEL PE 2025?

This BEL Probationary Engineer ECE 2025 paper contains 125 questions for practice with solutions and answer explanations.

Is BEL PE suitable for ECE students?

Yes. BEL Probationary Engineer Electronics/ECE papers strongly overlap with core ECE subjects such as networks, analog, digital, control, communication, signals and electromagnetic theory.

Which topics are most important for BEL PE?

Important BEL PE ECE areas include Analog Electronics, Communication Systems, Network Analysis, Control Systems, along with reasoning and aptitude practice.

Where can I practice BEL previous year papers?

You can practice BEL previous year papers on ECE Exam Guide using the BEL paper hub, solved paper pages and BEL practice section.