CBSE 12th Half-Yearly Exam 2025-26: Physics Top 50 MCQs with Answers

(a) [M⁰L⁰T¹A¹]

(b) [M¹L¹T¹A⁻¹]

(c) [M⁰L⁰T¹A]

(d) [M⁰L⁰T⁰A¹]

Ans. (a) [M⁰L⁰T¹A¹]

Q2. The SI unit of electric field is:

(a) Volt/meter

(b) Newton

(c) Joule

(d) Ampere

Ans. (a) Volt/meter

Q3. Two point charges +q and –q separated by distance 2a constitute:

(a) Electric monopole

(b) Electric dipole

(c) Quadrupole

(d) None

Ans. (b) Electric dipole

Q4. The electric field inside a conductor is:

(a) Zero

(b) Infinite

(c) Depends on charge

(d) None

Ans. (a) Zero

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Q5. The unit of capacitance is:

(a) Coulomb

(b) Volt

(c) Farad

(d) Ampere

Ans. (c) Farad

Q6. In a parallel plate capacitor, the capacitance increases when:

(a) Plate area decreases

(b) Distance between plates increases

(c) Dielectric constant increases

(d) None of these

Ans. (c) Dielectric constant increases

Q7. Ohm’s law is valid only when:

(a) Current is proportional to voltage

(b) Temperature remains constant

(c) Resistance remains constant

(d) All of these

Ans. (d) All of these

Q8. The resistivity of a conductor depends on:

(a) Length

(b) Area of cross-section

(c) Nature of material

(d) Shape

Ans. (c) Nature of material

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Q9. The SI unit of resistivity is:

(a) Ohm

(b) Ohm meter

(c) Ohm⁻¹ meter⁻¹

(d) Coulomb

Ans. (b) Ohm meter

Q10. In series combination of resistors:

(a) Same current flows

(b) Same voltage across each resistor

(c) Power is maximum

(d) Resistance decreases

Ans. (a) Same current flows

Q11. The magnetic field at the centre of a current-carrying circular loop is directly proportional to:

(a) Radius of loop

(b) Current

(c) Area

(d) Square of radius

Ans. (b) Current

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Q12. The SI unit of magnetic flux is:

(a) Weber

(b) Tesla

(c) Henry

(d) Joule

Ans. (a) Weber

Q13. A charged particle moving perpendicular to a uniform magnetic field will follow:

(a) Linear path

(b) Circular path

(c) Parabolic path

(d) Helical path

Ans. (b) Circular path

Q14. The device based on Fleming’s left-hand rule is:

(a) Galvanometer

(b) Motor

(c) Ammeter

(d) Voltmeter

Ans. (b) Motor

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Q15. Self-induction is the property of:

(a) Generating magnetic field

(b) Opposing change of current

(c) Producing emf in a conductor

(d) Increasing resistance

Ans. (b) Opposing change of current

Q16. The SI unit of inductance is:

(a) Henry

(b) Tesla

(c) Weber

(d) Joule

Ans. (a) Henry

Q17. The dimensional formula of inductance is:

(a) [ML²T⁻²A⁻²]

(b) [ML²T⁻²A⁻¹]

(c) [M⁰L²T⁻²A⁻²]

(d) [MLT⁻²A⁻²]

Ans. (a) [ML²T⁻²A⁻²]

Q18. The average value of AC current over one complete cycle is:

(a) Zero

(b) Maximum

(c) Half of maximum

(d) None

Ans. (a) Zero

Q19. The power factor of a pure capacitor is:

(a) Zero

(b) One

(c) Greater than one

(d) Infinity

Ans. (a) Zero

Q20. In an LCR circuit resonance occurs when:

(a) XL = XC

(b) XL > XC

(c) XL < XC

(d) None

Ans. (a) XL = XC

Q21. Which of the following electromagnetic waves has the highest frequency?

(a) Radio waves

(b) Gamma rays

(c) X-rays

(d) Ultraviolet rays

Ans. (b) Gamma rays

Q22. The speed of electromagnetic waves in vacuum is:

(a) 3 × 10⁸ m/s

(b) 3 × 10⁶ m/s

(c) 3 × 10⁵ m/s

(d) 3 × 10¹⁰ m/s

Ans. (a) 3 × 10⁸ m/s

Q23. The electromagnetic waves are:

(a) Longitudinal

(b) Transverse

(c) Stationary

(d) None

Ans. (b) Transverse

Q24. The SI unit of frequency is:

(a) Hertz

(b) Tesla

(c) Newton

(d) Joule

Ans. (a) Hertz

Q25. A convex lens of focal length 10 cm produces image at infinity when object distance is:

(a) 5 cm

(b) 10 cm

(c) 20 cm

(d) 15 cm

Ans. (b) 10 cm

Q26. Power of lens is measured in:

(a) Dioptre

(b) Joule

(c) Watt

(d) Weber

Ans. (a) Dioptre

Q27. The focal length of a plane mirror is:

(a) Zero

(b) Infinity

(c) Unity

(d) Depends on distance

Ans. (b) Infinity

Q28. The speed of light is maximum in:

(a) Glass

(b) Diamond

(c) Air

(d) Water

Ans. (c) Air

Q29. The angle of incidence for which angle of refraction is 90° is called:

(a) Angle of deviation

(b) Critical angle

(c) Brewster angle

(d) None

Ans. (b) Critical angle

Q30. In Young’s double-slit experiment, fringe width is proportional to:

(a) Wavelength

(b) Distance between slits

(c) Refractive index

(d) Frequency

Ans. (a) Wavelength

Q31. Polarization of light proves that light is:

(a) Longitudinal

(b) Transverse

(c) Both

(d) None

Ans. (b) Transverse

Q32. In photoelectric effect, the number of photoelectrons emitted is proportional to:

(a) Frequency of light

(b) Intensity of light

(c) Wavelength

(d) Threshold frequency

Ans. (b) Intensity of light

Q33. The photoelectric effect is explained by:

(a) Wave theory

(b) Quantum theory

(c) Electromagnetic theory

(d) Newton’s laws

Ans. (b) Quantum theory

Q34. Work function is measured in:

(a) Joule

(b) Electron volt

(c) Weber

(d) Henry

Ans. (b) Electron volt

Q35. The rest mass of photon is:

(a) Zero

(b) 1 kg

(c) Infinite

(d) 9.1 × 10⁻³¹ kg

Ans. (a) Zero 

Q36. In Bohr’s model, electrons revolve in:

(a) Continuous orbits

(b) Stationary orbits

(c) Random orbits

(d) Spiral paths

Ans. (b) Stationary orbits

Q37. The energy of an electron in the first orbit of hydrogen atom is:

(a) –13.6 eV

(b) –3.4 eV

(c) –1.51 eV

(d) –0.85 eV

Ans. (a) –13.6 eV

Q38. De Broglie wavelength of a particle is given by:

(a) h/p

(b) p/h

(c) hν

(d) h/m

Ans. (a) h/p

Q39. The uncertainty principle was proposed by:

(a) Einstein

(b) Heisenberg

(c) Planck

(d) Bohr

Ans. (b) Heisenberg

Q40. The charge of electron is:

(a) +1.6 × 10⁻¹⁹ C

(b) –1.6 × 10⁻¹⁹ C

(c) 1 C

(d) –1 C

Ans. (b) –1.6 × 10⁻¹⁹ C

Q41. Half-life of a radioactive element is the time in which:

(a) All atoms decay

(b) Half of atoms decay

(c) Activity becomes zero

(d) None

Ans. (b) Half of atoms decay

Q42. The SI unit of radioactivity is:

(a) Curie

(b) Rutherford

(c) Becquerel

(d) Tesla

Ans. (c) Becquerel

Q43. Nuclear fission is the:

(a) Splitting of a heavy nucleus

(b) Joining of light nuclei

(c) Decay of nucleus

(d) None

Ans. (a) Splitting of a heavy nucleus

Q44. Which of the following is used as a moderator in a nuclear reactor?

(a) Graphite

(b) Sodium

(c) Boron

(d) Lead

Ans. (a) Graphite

Q45. The binding energy per nucleon is maximum for:

(a) Uranium

(b) Iron

(c) Plutonium

(d) Thorium

Ans. (b) Iron

Q46. The SI unit of power is:

(a) Watt

(b) Joule

(c) Newton

(d) Ampere

Ans. (a) Watt

Q47. A body is said to be in equilibrium when:

(a) Net force = 0

(b) Net torque = 0

(c) Both (a) and (b)

(d) None

Ans. (c) Both (a) and (b)

Q48. The dimensional formula of velocity is:

(a) [LT⁻¹]

(b) [L²T⁻²]

(c) [LT]

(d) [M⁰L¹T⁻¹]

Ans. (a) [LT⁻¹]

Q49. A projectile has maximum range when angle of projection is:

(a) 30°

(b) 45°

(c) 60°

(d) 90°

Ans. (b) 45°

Q50. Work done is said to be positive when:

(a) Force and displacement are opposite

(b) Force is perpendicular to displacement

(c) Force and displacement are in same direction

(d) None

Ans. (c) Force and displacement are in same direction