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.
a) B
b) 4B
c) 2B
d) 8B.
b) 4B
Two wires of same length are shaped into a square and a circle. If they carry same current, the ratio of their magnetic moment-
a) 2:π
b)π:2
c) 4:π
d) π:4.
Two anti-parallel conducting wires carrying currents in the ratio 2:3. What is the nature of the force acting between them?
a) Attractive
b) Repulsive
c) Both attractive and Repulsive
d) can not predict.
The magnetic field at an outside point due to a long straight conductor carrying a constant current(I) is independent of
a) Material of the conductor
b) Radius of the conductor
c) Both (a) and (b)
d) Neither (a) nor (b)
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
The coil of a moving coil galvanometer is wound over a metal frame in order to-
(a) reduce hysteresis
(b) increase sensitivity
(c) increase moment of inertia
(d) provide electromagnetic damping.
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 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 .
In double –slit experiment the distance of the second dark fringe from the central line is 3 mm. The distance of the fourth bright fringe from the central line is
(A) 6 mm
(B) 8mm
(C) 12 mm
(D) 16 mm
In Young’s experiment with one source and two slits, one of the slits is covered with black paper. Then
(A) The fringes will be darker
(B) The fringes will be narrower
(C) The fringes will be broader
(D) No fringes will be obtained and the screen will have uniform illumination
A resistance of R Ω draws current from a potentiometer. The potentiometer has a total resistance \(R_0\) Ω as shown in the Fig below. A voltage V is supplied to the potentiometer. Derive an expression for the voltage across R when the sliding contact is in the middle of the potentiometer.
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
In a Wheatstone bridge, three resistors P,Q, R are connected in three arms in order and 4th arm of resistance, s, is formed by two resistors s1 and s2 connected in parallel. The condition for bridge to be balanced is, P/Q
To convert a moving coil galvanometer into on ammeter of given range, we must connect:
(a) A suitable low resistance in series
(b) A suitable low resistance in parallel
(c) A suitable high resistance in parallel
(d) A suitable high resistance in series
A wavefront of a wave has direction with wave motion
(A) Parallel
(B) Perpendicular
(C) opposite
(D) at any angle θ