Advertisements
Advertisements
Question
A closely wound circular coil of radius 0.02 m is placed perpendicular to the magnetic field. When the magnetic field is changed from 8000 T to 2000 T in 6 s, an emf of 44 V is induced in it. Calculate the number of turns in the coil.
Advertisements
Solution
Given data:
radius r = 0.02 m
Q = 90° – 90° = 0°
B1 = 8000 T, B2 = 2000 T
dt = 68
ε = 68V
n = ?
ε = nA cos θ `"dB"/"dt"`
`44 = "n" xx pi xx 0.02 xx 0.02 xx cos theta xx ((8000 - 2000)/6)`
`44 = "n" xx 22/7 xx 4 xx 10^4 xx 1 xx 6000/6`
n = `(44 xx 7 xx 6)/(22 xx 4 xx 10^-4 xx 6000)`
`= 7/(2 xx 10^-1) = 70/2`
n = 35 turns
APPEARS IN
RELATED QUESTIONS
When an electric current is passed through any wire, a magnetic field is produced around it. Then why an electric iron connecting cable does not attract nearby iron objects when electric current switched on through it?
When the magnet shown in the diagram below is moving towards the coil, the galvanometer gives a reading to the right.
() What is the name of the effect being produced by the moving magnet?
(2) State what happens to the reading shown on the galvanometer when the magnet is moving away from the coil.
(3) The original experiment is repeated. This time the magnet is moved towards the coil at a great speed. State two changes you would notice in the reading on the galvanometer.
A conducting square loop having edges of length 2.0 cm is rotated through 180° about a diagonal in 0.20 s. A magnetic field B exists in the region which is perpendicular to the loop in its initial position. If the average induced emf during the rotation is 20 mV, find the magnitude of the magnetic field.
Figure shows a wire sliding on two parallel, conducting rails placed at a separation l. A magnetic field B exists in a direction perpendicular to the plane of the rails. What force is necessary to keep the wire moving at a constant velocity v?
Why soft iron is preferred to be used as the core of the electromagnet of an electric bell?
State the condition at which we say the two coils kept close to each other are perfectly coupled with each other.
What for an inductor is used? Give some examples.
A square coil of side 30 cm with 500 turns is kept in a uniform magnetic field of 0.4 T. The plane of the coil is inclined at an angle of 30° to the field. Calculate the magnetic flux through the coil.
Ansari Sir was demonstrating an experiment in his class with the setup as shown in the figure below.
A magnet is attached to a spring. The magnet can go in and out of the stationary coil. He lifted the Magnet and released it to make it oscillate through the coil.
Based on your understanding of the phenomenon, answer the following question.
Consider the situation where the Magnet goes in and out of the coil. State two changes which could be made to increase the deflection in the galvanometer.
A coil of one turn is made of a wire of certain length and then from the same length, a coil of two turns is made. If the same current is passed in both the cases, then the ratio of the magnetic inductions at their centres will be:
