NEET Physics MCQs - Electricity, Magnetism and Optics (Set 3)

Q1. Two identical small metal spheres carry charges of +6 μC and −2 μC and attract each other with force F. They are touched together and returned to the same separation. What is the new force between them?

a) 3F, repulsive

b) F, repulsive

c) F/3, attractive

d) F/3, repulsive

Q2. An electron starting from rest is accelerated through a potential difference of 1000 V. What kinetic energy does it gain? (e = 1.6 × 10⁻¹⁹ C)

a) 1.6 × 10⁻²² J

b) 1.6 × 10⁻¹⁶ J

c) 1.6 × 10⁻¹⁹ J

d) 6.25 × 10²¹ J

Q3. A 2 μF capacitor charged to 100 V is connected across an uncharged 2 μF capacitor. How much energy is lost as heat during charge sharing?

a) 0.01 J

b) 0.005 J

c) 0.0025 J

d) 0

Q4. Two 6 μF capacitors are connected in series, and this pair is connected in parallel with a 3 μF capacitor. What is the equivalent capacitance?

a) 15 μF

b) 6 μF

c) 9 μF

d) 2 μF

Q5. How many electrons pass through a cross-section of a wire each second when it carries a steady current of 1 A? (e = 1.6 × 10⁻¹⁹ C)

a) 6.25 × 10¹⁹

b) 1.6 × 10¹⁸

c) 6.25 × 10¹⁸

d) 1.6 × 10¹⁹

Q6. A metal wire has a resistance of 10 Ω at 0 °C and a temperature coefficient of resistance of 0.004 °C⁻¹. What is its resistance at 50 °C?

a) 20 Ω

b) 10.2 Ω

c) 14 Ω

d) 12 Ω

Q7. An electric heater is rated 1000 W, 220 V. What power does it consume when operated on a 110 V supply? (Assume its resistance stays constant)

a) 125 W

b) 1000 W

c) 500 W

d) 250 W

Q8. A straight wire 2 m long carries a current of 5 A in a uniform magnetic field of 0.2 T. The wire makes an angle of 30° with the field. What force acts on it?

a) √3 N

b) 2 N

c) 0.5 N

d) 1 N

Q9. A galvanometer of resistance 100 Ω gives full-scale deflection at 10 mA. What shunt resistance converts it into an ammeter of range 0 to 1 A?

a) About 9.9 Ω

b) About 1.01 Ω

c) About 0.1 Ω

d) About 99 Ω

Q10. The magnetic flux through each turn of a 100-turn coil falls from 0.02 Wb to 0.005 Wb in 0.1 s. What is the average induced EMF?

a) 15 V

b) 1.5 V

c) 0.15 V

d) 150 V

Q11. An ideal transformer steps 2200 V down to 220 V. Its primary coil has 500 turns. How many turns does the secondary coil have?

a) 5000

b) 500

c) 50

d) 5

Q12. Which statement is true for a series LCR circuit at resonance?

a) The power factor is zero

b) The impedance equals R and the current is in phase with the voltage

c) The current leads the voltage by 90°

d) The impedance is maximum and the current is minimum

Q13. An object is placed 20 cm in front of a convex mirror of focal length 20 cm. Where is the image formed?

a) 20 cm behind the mirror, virtual and the same size

b) 10 cm in front of the mirror, real and inverted

c) 10 cm behind the mirror, virtual, erect and half the size

d) At infinity

Q14. A prism with refracting angle 60° gives a minimum deviation of 30°. What is the refractive index of its material?

a) 2

b) √2

c) 1.5

d) √3

Q15. An astronomical telescope has an objective of focal length 100 cm and an eyepiece of focal length 5 cm. In normal adjustment, what are its magnifying power and tube length?

a) 20 and 95 cm

b) 500 and 105 cm

c) 5 and 100 cm

d) 20 and 105 cm