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NEET - Physics Magnetism in Electric Current Test Yourself

23513.In cyclotron, for a given magnet, radius of the semicircle traced by positive ion is directly proportional to
(v = velocity of positive ion)
v–2
v–1
v
v2
23514.A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the centre of the loop is B. It is then bent into a circular coil of n turns. The magnetic field at the centre of this coil of n turns will be
nB
n2B
2nB
2n2B
23515.A circular loop of radius 0.3 cm lies parallel to a much bigger circular loop of radius 20 cm. The centre of the small loop is on the axis of the bigger loop. The distance between their centres is 15 cm. If a current of 2.0 A flows through the smaller loop, then the flux linked with bigger loop is
9.1 × 10–11 weber
6 × 10–11 weber
3.3 × 10–11 weber
6.6 × 10–9 weber
23516.Two parallel wires 1 m apart carry currents of 1 A and 3 A respectively in opposite directions. The force per unit length acting between two wires is
6 × 10–5 Nm–1 repulsive
6 × 10–7 Nm–1 repulsive
6 × 10–5 Nm–1 attractive
6 × 10–7 Nm–1 attractive
23517.Sensitivity of a moving coil galvanometer can be increased by
decreasing the number of turns of coil
increasing the number of turns of coil
decreasing the area of a coil
by using a weak magnet
23518.A range of galvanometer is ‘V’, when 50 Ω resistance is connected in series. Its range gets doubled when 500 Ω resistance is connected in series. Galvanometer resistance is
100 Ω
200 Ω
300 Ω
400 Ω
23519.Two concentric coils each of radius equal to 2π cm are placed right angles to each other. If 3A and 4A are the currents flowing through the two coils respectively. The magnetic induction (in Wb m–2) at the center of the coils will be
5 × 10–5
12 × 10–5
7 × 10–5
10–5
23520.A current loop in a magnetic field
Experiences a torque whether the field is uniform or non uniform in all orientations
Can be in equilibrium in one orientation
Can be in equilibrium in two orientations, both the equilibrium states are unstable
Can be in equilibrium in two orientations, one stable while the other is unstable
23521.A galvanometer having internal resistance 10 Ω requires 0.01 A for a full scale deflection. To convert this galvanometer to a voltmeter of full–scale deflection at 120V, we need to connect a resistance of
11990 Ω in series
11990 Ω in parallel
12010 Ω in series
12010 Ω in parallel
23522.In the cyclotron, as radius of the circular path of the charged particle increases (ω = angular velocity, v = linear velocity)
v increases, ω remains constant
both ω and v increases
v increases, ω decreases
ω only increases, v remains constant
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