All Free Physics MCQs with Answers
Every Physics question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
13,934 questions · page 656 of 697
- A. 5 days
- B. 4 days
- C. 10 days
- D. 6 days
Explanation: Radioactive decay is an exponential decay process. Half life measures the time it takes for a given amount of the substance to become…
Correct answer: 4 days13102. The relation between the decay constant 'λ' and the half-life T12 of a radioactive substance is:
- A. λ = 1/T1/2
- B. λ = 0693 T1/2
- C. λ = T1/2
- D. λ = 0.693/T1/2
Explanation: The time required for half of the original population of radioactive atoms to decay is called the half-life.
Correct answer: λ = 0.693/T1/2- A. 25g
- B. 50g
- C. 100g
- D. 200g
Explanation: After every half life, the amount of uranium halves. Following this idea, after the first half life, the amount of uranium drops from 400g…
Correct answer: 50g- A. 11.4 m/s.
- B. 19.6 m/s.
- C. 22.8 m/s.
- D. 9.8 m/s.
Explanation: The problem involves applying the conservation of energy principle. Initially, the disc is at rest at the top of the hill, possessing only…
Correct answer: 19.6 m/s.- A. (P2 t2)/m
- B. (P2 t2)/2m
- C. (P2 t2)/3m
- D. (P2 t2)/4m
Explanation: The kinetic energy of a particle is given by the formula: KE = ½ mv² In this case, the particle is initially at rest, so its initial…
Correct answer: (P2 t2)/2m- A. [ML-2T-1]
- B. [ML-2T-2]
- C. [M2L-2T-1]
- D. [M-1L3T-2]
Explanation: Explanation: F = G (m1) (m2) / r² G = F (r²) / (m1) (m2) G = [MLT-2] [L²] / [M] [M] = [M-1L³T-2] These dimensions correspond to surface…
Correct answer: [M-1L3T-2]- A. emf.
- B. Resistance.
- C. Shear
- D. Currents.
Explanation: Lenz's law refers to induced currents and not to induced EMF, which means that we can apply it directly to closed conducting loops or…
Correct answer: Currents.- A. 24 sec
- B. 2 sec
- C. 12 sec
- D. 8 sec
Explanation: To solve this problem, use the impulse-momentum theorem, which states that the impulse (force multiplied by time) is equal to the change…
Correct answer: 2 sec- A. 4π x 10-7 WbA-1m-1
- B. 4π x 102 WbA-2m-2
- C. 4π x 10-7 WbA-2m-1
- D. 4π x 102 WbA-1m-2
Explanation: Explanation: The value of permeability of free space μo is 4π × 10-7 WbA-1m-1.
Correct answer: 4π x 10-7 WbA-1m-1- A. 1 Wb m-2 = N m-1 A-1
- B. 1 Tesla = 104 Gauss
- C. 1 Wb m-2 = 1 Tesla
- D. All of these
Explanation: Option D is the correct choice because all the given relations are accurate.
Correct answer: All of these- A. τ = NIAB cos α
- B. τ = BIL sin α
- C. τ = NIAB sin α
- D. τ = BIL cos α
Explanation: The correct formula for the torque acting on a current-carrying coil is τ = NIAB cos α.
Correct answer: τ = NIAB cos α- A. Increasing magnetic field
- B. Increasing the number of turns of the coil
- C. Increasing the c/BAN ratio
- D. Decreasing the length of couple 'c'
Explanation: Sensitivity of a galvanometer is defined as the deflection per unit current.
Correct answer: Increasing the c/BAN ratio- A. F = NIA cos α
- B. F = μnI
- C. F = ILB sin α
- D. F = ILA cos α
Explanation: The correct formula for the force exerted on a current-carrying conductor in a uniform magnetic field is F = ILB sin α.
Correct answer: F = ILB sin α- A. F/2
- B. 2F
- C. F/√2
- D. √2 F
Explanation: As we know, the force experienced by the current-carrying conductor is given by F'=IBLsinθ If θ= 45o F'=Fsin45° F'=F(0.707) F'=F/√2
Correct answer: F/√2- A. Half
- B. Double
- C. Eight-times
- D. Four-times
Explanation: As we know, the force experienced by the current-carrying conductor is given by F=IBL (sinθ=1) F'=IBLsinθ If = 90o If all other…
Correct answer: Eight-times- A. 0°
- B. 30°
- C. 90°
- D. 60°
Explanation: The maximum force on a current-carrying conductor occurs when the current direction and the magnetic field's direction are perpendicular…
Correct answer: 90°- A. Parallel to the conductor
- B. In clockwise direction
- C. Anticlockwise direction
- D. None of these
Explanation: The direction of magnetic field in the conductor can be found out by right hand thumb rule.
Correct answer: Anticlockwise direction13118. 1 Gauss is equivalent to:
- A. 1 tesla
- B. 10-3tesla
- C. 10 tesla
- D. 10-4tesla
Explanation: We know that:1 Tesla = 104Gauss=> 1 gauss = 10-4 TeslaBoth Tesla and Gauss are units of magnetic induction.Electromagnetic or magnetic…
Correct answer: 10-4tesla- A. An isolated magnetic pole
- B. Static electric charge
- C. Nonmagnetic substance
- D. Current loop
Explanation: A current loop, such as a wire carrying electric current in a circular path, creates a magnetic field around it.
Correct answer: Current loop- A. Lines start at north pole and ends at south pole
- B. Lines never touch or cross each other
- C. The lines are curved
- D. The magnetic field is strongest when the lines are farthest.
Explanation: Option D is Incorrect because the magnetic field is strongest where the lines are closest together, indicating a higher field strength.
Correct answer: The magnetic field is strongest when the lines are farthest.