Home

Theory For Notes Making

Objective Assignment

Subjective Assignment

On Line Test

Video Lecture

Theory For Notes Making

Objective Assignment

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.

Subjective Assignment

Q.1

The motion of copper plate is damped when it is allowed to oscillate between the two poles of a magnet. What is the cause of this damping ?

Q.2

A light metal disc on the top of an electromagnetic is thrown up as the current is switched on. Why ? Give reason.

Q.3

Why does a metallic piece become very hot when it is surrounded by a coil carrying high frequency alternating current?

Q.4

What are eddy currents? Discuss briefly any two applications of eddy currents/

Q.5

What are eddy currents? Give some applications of eddy currents. How can the eddy currents be minimized?

Q.6

A line charge λ per unit length is lodged uniformly onto the rim of a wheel of mass M and radius R. The wheel has light non-conducting spokes and is free to rotate without friction about its axis (Fig.) . A uniform magnetic field extends over a circular region within the rim. It is given by,                                          \displaystyle B\,=\,-{{B}_{0}}k \displaystyle \left( {r\,\le \,a\,:\,a\,<\,R} \right) = 0         (otherwise)

What is the angular velocity of the wheel after the field is suddenly switched off?

Ans.    \displaystyle -\frac{{B\pi {{a}^{2}}\lambda }}{{MR}}

Q.7

Figure shows a square loop of side L perpendicular to the uniform field of a solenoid. (a) Show that at any point on a side the component of the induced electric field along the side is \frac{1}{4}L dB/dt.

(b) Evaluate \oint{{\vec{E}}}. d \vec{l} around the loop.

Ans.   L2 \frac{{dB}}{{dt}}

QUIZ

0
Created on By physicscart

Feddy Current And Induced Electric Field Due To Time Varying Magnetic Field (Basic Level)

1 / 10

Eddy currents are produced when

2 / 10

Plane of eddy currents makes an angle with the plane of magnetic lines of force equal to

3 / 10

Use of eddy currents is done in the following except

4 / 10

An inductance L and a resistance R are first connected to a battery. After some time the battery is disconnected but L and R remain connected in a closed circuit. Then the current reduces to 37% of its initial value in

5 / 10

A solenoid has 2000 turns wound over a length of 0.30 metre. The area of its cross-section is 1.2\times {{10}^{{-3}}}{{m}^{2}}. Around its central section, a coil of 300 turns is wound. If an initial current of 2 A in the solenoid is reversed in 0.25 sec, then the e.m.f. induced in the coil is

6 / 10

When the electrical conductivity of a semi-  conductor  is due to the breaking of its covalent bonds, then the semiconductor is said to be

7 / 10

A hemispherical bowl just floats without sinking in a liquid of  density 1.2 × 103kg/m3. If outer diameter and the density of the bowl are 1 m and 2 × 104 kg/m3 respectively, then the inner diameter of the bowl will be

8 / 10

There is a hemispherical bowl of radius R. A block of mass m slides without friction from the rim of the bowl to the bottom. The velocity of the block at the bottom will be

9 / 10

Two rails of a railway track insulated from each other and the ground are connected to a milli voltmeter. What is the reading of voltmeter, when a train travels with a speed of 180 km/hr along the track. Given that the vertical component of earth's magnetic field is 0.2\times {{10}^{{-4}}}weber/{{m}^{2}} and the rails are separated by 1 metre n

10 / 10

A copper ring is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring. The acceleration of the falling magnet while it is passing through the ring is

Your score is

The average score is 0%

LinkedIn Facebook VKontakte
0%