Advertisements
Advertisements
प्रश्न
A conducting rod is moved with a constant velocity v in a magnetic field. A potential difference appears across the two ends _____________ .
विकल्प
if `vec v " || "vec l`
if `vec v " || "vec B`
if `vec l " || "vec B`
None of these
Advertisements
उत्तर
None of these
The potential difference across the two ends is given by
`e=Bvl`
It is non-zero only
(i) if the rod is moving in the direction perpendicular to the magnetic field `(vec v bot vec B)`
(ii) if the velocity of the rod is in the direction perpendicular to the length of the rod `(vec v bot vec l)`
(iii) if the magnetic field is perpendicular to the length of the rod `vec l bot vec B`
Thus, none of the above conditions is satisfied in the alternatives given.
APPEARS IN
संबंधित प्रश्न
When a bar magnet is pushed towards (or away) from the coil connected to a galvanometer, the pointer in the galvanometer deflects. Identify the phenomenon causing this deflection and write the factors on which the amount and direction of the deflection depends. State the laws describing this phenomenon.
How does an electromagnet differ forma permanent magnet?
What condition is necessary for the production of current by electromagnetic induction?
An induced current is produced when a magnet is moved into a coil. The magnitude of induced current does not depend on:
(a) the speed with which the magnet is moved
(b) the number of turns of the coil
(c) the resistivity of the wire of the coil
(d) the strength of the magnet
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.
Name and state the law which determines the direction of induced current.
or
State Fleming’s right-hand rule.
The following diagram shows a fixed coil of several turns connected to a center zero galvanometer G and a magnet NS which can move in the direction shown in the diagram.
- Describe the observation in the galvanometer if
- The magnet is moved rapidly,
- The magnet is kept still after it has moved into the coil
- The magnet is then rapidly pulled out the coil.
- How would the observation in (i) of part (a) change if a more powerful magnet is used?
A transformer has 400 turns in the primary winding and 10 turns in the secondary winding. The primary e.m.f. is 250 V and the primary current is 2.0 A. calculate:
(a) The secondary voltage,
(b) The secondary current, assuming 100% efficiency.
Complete the following diagram of a transformer and name the parts labeled A and B. Name the part you have drawn to complete the diagram . What is the material of this part? In this transformer a step-up or step-down? Why?
You have been provided with a solenoid AB.
(i) What is the polarity at end A?
(ii) Give one advantage of an electromagnet over a permanent magnet.
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.
Using Lenz’s law, predict the direction of induced current in conducting rings 1 and 2 when the current in the wire is steadily decreasing.
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 0.4 m wire, stretched horizontally, carries an electric current of 15 A, in a magnetic field whose magnetic field intensity is 0.1 N/Am. What is the magnitude of the wire?
The primary of a transformer has 400 turns while the secondary has 2000 turns. If the power output from the secondary at 1000 Vis 12 kW, what is the primary voltage?
Show that for a given positive ion species in a cyclotron, (i) the radius of their circular path inside a dee is directly proportional to their speed, and (ii) the maximum ion energy achievable is directly proportional to the square of the magnetic induction.
Which scientists established in the early nineteenth century that electricity and magnetism are related?
Which device used for using electricity developed from Faraday’s and Henry’s experiments?
