Class 12 Physics – Daily Revision MCQ (English Medium)
Timed quiz: 15 seconds per question, the next one loads by itself when time runs out. Or solve without the timer: tap an option, right turns green, wrong turns red. 10 new questions every morning at 8.
Or scroll down and solve without the timer.
A car takes a turn of radius 20 m on a level (unbanked) road. The coefficient of static friction between the tyres and the road is 0.5. What is the maximum speed at which it can take the turn without skidding? (g = 10 m/s²)
Chapter 1: Rotational Dynamics
Show answer
Answer: B. 10 m/s
On a level road friction alone gives the centripetal force: v(max) = √(μrg) = √(0.5 × 20 × 10) = √100 = 10 m/s.In a glass capillary tube dipped in mercury, the mercury level inside stays below the outside level. This is because the angle of contact between mercury and glass is:
Chapter 2: Mechanical Properties of Fluids
Show answer
Answer: D. obtuse
Mercury does not wet glass; its angle of contact with glass is obtuse, so the meniscus is convex and mercury falls in the capillary.The absolute temperature of a perfect blackbody is doubled. The energy it radiates per unit area per unit time becomes:
Chapter 3: Kinetic Theory of Gases and Radiation
Show answer
Answer: C. 16 times
By the Stefan-Boltzmann law, energy radiated ∝ T⁴, so doubling T gives 2⁴ = 16 times the energy.A Carnot engine works between a source at 500 K and a sink at 300 K. Its efficiency is:
Chapter 4: Thermodynamics
Show answer
Answer: A. 40%
η = 1 − Tc/TH = 1 − 300/500 = 1 − 0.6 = 0.4, i.e. 40%.A particle performs simple harmonic motion. If its amplitude is doubled while the force constant stays the same, its total energy becomes:
Chapter 5: Oscillations
Show answer
Answer: C. 4 times
Total energy in SHM is E = ½ k A², so it is proportional to A²; doubling A makes E four times.In Young's double slit experiment, light of wavelength 600 nm is used, the slit separation is 1 mm and the screen is 1 m away. The fringe width is:
Chapter 7: Wave Optics
Show answer
Answer: B. 0.6 mm
Fringe width = λD/d = (600 × 10⁻⁹ m × 1 m) / (1 × 10⁻³ m) = 6 × 10⁻⁴ m = 0.6 mm.Three capacitors of 6 μF each are connected in series. Their equivalent capacitance is:
Chapter 8: Electrostatics
Show answer
Answer: D. 2 μF
In series, 1/Cs = 1/6 + 1/6 + 1/6 = 3/6 = 1/2, so Cs = 2 μF.If the momentum of a moving electron is doubled, its de Broglie wavelength becomes:
Chapter 14: Dual Nature of Radiation and Matter
Show answer
Answer: A. half
de Broglie wavelength λ = h/p, so it is inversely proportional to momentum; doubling p halves λ.According to Bohr's model, the radius of the third orbit of the hydrogen atom is how many times the radius of its first orbit?
Chapter 15: Structure of Atoms and Nuclei
Show answer
Answer: D. 9
In Bohr's model rₙ ∝ n², so r₃/r₁ = 3²/1² = 9.The output of a two-input NAND gate is 0 (LOW) only when:
Chapter 16: Semiconductor Devices
Show answer
Answer: B. both inputs are 1
A NAND gate is an AND gate followed by a NOT gate: AND gives 1 only when both inputs are 1, so NAND gives 0 only in that case.
Class 12: MCQ in other subjects
Previous days
All questions are written by PadhaiNotes in our own words from the chapters of the official Maharashtra State Board Balbharati textbook (ebalbharati.in). Each question shows its chapter.