NEET Physics 5 — Questions and Answers
Question 1: A current-carrying conductor is placed in a magnetic field. The force on the conductor is zero when the angle between the current direction and magnetic field is:
- 0° (Correct answer)
- 90°
- 45°
- 180°
Correct answer: 0°
The force on a conductor F = BIL sinθ is zero when θ = 0° or 180° (current parallel to field), but θ = 0° is the standard answer.
Question 2: In an AC circuit, the phase difference between voltage and current in a pure capacitor is:
- Current leads voltage by 90° (Correct answer)
- Voltage leads current by 90°
- They are in phase
- Current leads voltage by 45°
Correct answer: Current leads voltage by 90°
In a pure capacitive circuit, the current leads the applied voltage by 90° (π/2 radians).
Question 3: The SI unit of magnetic flux is:
- Weber (Wb) (Correct answer)
- Tesla (T)
- Henry (H)
- Ampere (A)
Correct answer: Weber (Wb)
Magnetic flux Φ = B·A is measured in Weber (Wb), where 1 Wb = 1 T·m².
Question 4: A transformer has 500 primary turns and 50 secondary turns. If the primary voltage is 220 V, the secondary voltage is:
- 22 V (Correct answer)
- 220 V
- 2200 V
- 110 V
Correct answer: 22 V
Using V₂/V₁ = N₂/N₁: V₂ = 220 × (50/500) = 22 V.
Question 5: The electric field inside a charged hollow spherical conductor is:
- Zero (Correct answer)
- Uniform and non-zero
- Inversely proportional to radius
- Equal to the field on the surface
Correct answer: Zero
By Gauss's law, the electric field inside a hollow charged conductor is zero because no charge resides inside.
Question 6: Two capacitors of capacitance C each are connected in series. The equivalent capacitance is:
- C/2 (Correct answer)
- 2C
- C
- C²
Correct answer: C/2
For capacitors in series: 1/C_eq = 1/C + 1/C = 2/C, so C_eq = C/2.
Question 7: The phenomenon of electromagnetic induction was discovered by:
- Michael Faraday (Correct answer)
- James Clerk Maxwell
- Heinrich Hertz
- André-Marie Ampère
Correct answer: Michael Faraday
Michael Faraday discovered electromagnetic induction in 1831, showing that a changing magnetic flux induces an EMF.
NEET Physics 5
A current-carrying conductor is placed in a magnetic field.
The force on the conductor is zero when the angle between the current direction and magnetic field is: