BPSC CCE Prelims
Physics Previous Year Questions (PYQs)
Showing solved Previous Year Questions for Chapter: Physics
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We apply a force of 200 Newtons on a wooden Box and push it on the floor at constant velocity. The marginal friction force will be:
Detailed Explanation:
Constant velocity means net force = 0, so applied force equals friction force.
Applied force = 200 N, therefore kinetic friction = 200 N.
A truck starts from rest down a hill with a constant acceleration. It achieves 400 meters in 20 seconds. If the weight of the truck is 7 tons then what will be the force acting on it?
Detailed Explanation:
Given: Initial velocity u = 0 (starts from rest), displacement s = 400 m, time t = 20 s, mass m = 7 tons = 7000 kg.
Step 1 – Find acceleration: Using s = ut + ½at²
400 = 0 + ½ × a × (20)²
400 = 200a
a = 2 m/s²
Step 2 – Calculate force: Using F = ma
F = 7000 × 2
F = 14000 N
Answer: 14000 Newtons
Energy consumed in a home is 250 units then the total energy in Joule will be:
Detailed Explanation:
1 unit of electrical energy = 1 kWh = 3.6 × 10⁶ joules.
250 units = 250 × 3.6 × 10⁶ J = 900 × 10⁶ J = 9 × 10⁸ J.
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In which medium, the speed of sound is maximum?
Detailed Explanation:
Speed of sound depends on elasticity and density of the medium — highest in solids, moderate in liquids, lowest in gases.
Steel (solid) ≈ 5000–6000 m/s, Water (liquid) ≈ 1500 m/s, Air (gas) ≈ 343 m/s, Hydrogen (gas) ≈ 1284 m/s. Among given options, steel has maximum speed.
The potential energy of a freely falling body continuously decreases.
Detailed Explanation:
Potential energy (PE) decreases as height decreases during free fall, while kinetic energy (KE) increases due to increasing velocity.
Total mechanical energy (PE + KE) remains constant throughout the fall, demonstrating that the law of conservation of energy is not violated—energy transforms from one form to another but is neither created nor destroyed.
A pair of Oxen exerts a force of 140 newton while ploughing the field. The field ploughed is 15 meter long. The work done in ploughing the length of the field is:
Detailed Explanation:
Work done is calculated using the formula W = F × d, where F is force and d is distance.
Given Force = 140 N and Distance = 15 m, substituting values: W = 140 × 15 = 2100 Joule.
The focal distance of a plane mirror is
Detailed Explanation:
Focal length of a mirror is f = R/2, where R is the radius of curvature.
A plane mirror has zero curvature (flat surface), so R = ∞. Therefore, f = ∞/2 = ∞. Parallel rays reflecting from a plane mirror remain parallel and never converge or diverge to form a focus point.
Which term in the following does not denote the electric power în electric circuit?
Detailed Explanation:
Electric power in a circuit is given by P = VI (voltage × current).
Using Ohm's law (V = IR), we can derive two more valid formulas:
• P = I²R (substituting V = IR into P = VI)
• P = V²/R (substituting I = V/R into P = VI)
✅ Option 2 (I²R): Valid power formula.
✅ Option 3 (VI): Fundamental definition of power.
✅ Option 4 (V²/R): Valid derived formula.
❌ Option 1 (IR²): Not a valid power formula. Its dimensional analysis gives (Ampere × Ohm²), which does not equal Watt (power unit).
In short circuit, the value of electric current in a time circuit:
Detailed Explanation:
Short circuit occurs when a path of nearly zero resistance forms in a circuit, bypassing the normal load.
According to Ohm's Law (I = V/R), when resistance R approaches zero, the current I increases dramatically to very high values, limited only by the internal resistance of the source.
This surge can cause overheating, fires, and equipment damage, which is why fuses and circuit breakers are used for protection.
What is the device to protect equipments from the electric shock?
Detailed Explanation:
Fuse is a safety device containing a thin wire with low melting point that melts and breaks the circuit when excess current flows, protecting equipment from electric shock, overload, and short circuits.
Generator produces electricity, Motor converts electrical to mechanical energy, and Current controller regulates current but does not automatically disconnect during faults—only the fuse provides automatic protection.
Reactance of a capacitor is
Detailed Explanation:
Capacitive reactance (Xc) is given by the formula Xc = 1/(2πfC), where f is frequency and C is capacitance.
Since f appears in the denominator, as frequency increases, reactance decreases — meaning Xc ∝ 1/f (inversely proportional to frequency).
There is no atmosphere on the surface of the moon because
Detailed Explanation:
The Moon lacks an atmosphere because its escape velocity (2.38 km/s) is lower than the root mean square (rms) velocity of gas molecules like hydrogen and helium (1–1.5 km/s).
When the rms velocity exceeds escape velocity, gas molecules possess enough kinetic energy to overcome the Moon's weak gravitational pull and escape into space. In contrast, Earth's escape velocity (11.2 km/s) is sufficiently high to retain atmospheric gases.
In the following question, out of four words given below, three are alike in some manner and fourth word is different. Find the different one.
Detailed Explanation:
Telescope, Microscope, and Periscope are optical instruments that use lenses and mirrors to view objects (distant, tiny, or around obstacles).
Stethoscope is an acoustic medical device used to listen to internal body sounds (heartbeat, lung sounds), not for viewing.
As the diameter of objective lens of a telescope increases, the resolution of telescope
Detailed Explanation:
Resolution of a telescope is its ability to distinguish between two closely spaced objects and is inversely proportional to the angular resolution θ.
According to Rayleigh's criterion, θ = 1.22λ/D, where λ is the wavelength of light and D is the diameter of the objective lens. As D increases, θ decreases, meaning the telescope can resolve finer details — hence resolution increases.
A larger aperture also collects more light, further improving image clarity and the ability to separate closely spaced objects.
Compared to a burn due to air at 100°C, the burn due to steam at 100°C is
Detailed Explanation:
Steam at 100°C contains latent heat of vaporization (540 cal/g) in addition to thermal energy, while air at 100°C has only thermal energy.
When steam condenses on skin, it releases this extra latent heat, transferring significantly more total energy than hot air, causing deeper and more severe burns.