A 40 mF capacitor is connected to a 200 V, 50 Hz ac supply. The r.m.s value of the current in the circuit is, nearly (a) 1.7 A (b) 2.05 A (c) 2.5 A (d) 25.1 A

A bar magnet of dipole moment ’m’ cut into two equal pieces transverse to its length. Dipole moment of each part is a) Remain same b) m/2 c) 2m d) none of the above

A capacitor of capacity C has reactance X. If capacitance and frequency become double then reactance will be (a) 4X (b) X/2 (c) X/4 (d) 2X

A coil of N turns and mean cross-sectional area A is rotating with uniform angular velocity ω about an axis at right angle to uniform magnetic field B. The induced emf in the coil will be (a) NBAsinωt (b) NBωsinωt (c) NB/Asinωt (d) NBAωsinωt

A Daniel cell is balanced on 125 cm length of a potentiometer wire. When the cell is short circuited with a 2 Ω resistance, the balancing length obtained is 100 cm. Internal resistance of the cell will be (a) 1.5 Ω (b) 0.5 Ω (c) 1.25 Ω (d) 4/5 Ω

A Galvanometer is said to be sensitive, when- a) Small deflection for a small current b) Small deflection for a large current c) large deflection for a small current d) large deflection for a large current .

A Galvanometer of resistance 10 Ω gives full-scale deflection when 1 mA current passes through it. The resistance required to convert it into a voltmeter reading upto 2.5 Volt is; a) 9800 Ω b) 2490 Ω c) 4980 Ω d) 9880 Ω.

A new flashlight cell of emf 1.5 volts gives a current of 15 amps, when connected directly to an ammeter of resistance 0.04 Ω. The internal resistance of cell is (a) 0.04 Ω (b) 0.06 Ω (c) 0.10 Ω (d) 10 Ω

A small signal voltage V(t) = V₀ sin(ωt) is applied across an ideal capacitor C (a) Current I(t) is in phase with voltage V(t). (b) Current I(t) leads voltage V(t) by 180°. (c) Current I(t), lags voltage V(t) by 90°. (d) Over a full cycle the capacitor C does not consume any energy from the voltage source

A solenoid has 1000 turns per metre length. If a current of 5A is flowing through it, then magnetic field inside the solenoid is-

A torch bulb rated as 4.5 W, 1.5 V is connected as shown in the figure. The emf of the cell needed to make the bulb glow at full intensity is (a) 4.5 V (b) 1.5 V (c) 2.67 V (d) 13.5 V

A transformer having efficiency of 90% is working on 200 V and 3 kW power supply. If the current in the secondary coil is 6 A, the voltage across the secondary coil and the current in the primary coil respectively are (a) 300 V, 15 A (b) 450 V, 15 A (c) 450 V, 13.5 A (d) 600 V, 5 A

A wire in the form of a circular loop, of one turn carrying a current, produces magnetic induction B at the centre. If the same wire is looped into a coil of two turns and carries the same current, the new value of magnetic induction at the centre is- a) B b) 4B c) 2B d) 8B.

An alpha particle is moving perpendicularly to a uniform magnetic field of 3 Tesla with the velocity m/s. What is the work done by the particle? (a) 30 × 10⁶ J (b) 60 × 10⁶ J (c) infinity (d) zero

An electron initially at rest is accelerated through a potential difference of one volt. The energy gained by electron is: (a) 1 J (b) 1.6 × \(10^{-19}\) J (c) \(10^{-19}\) J (d) None of these