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प्रश्न
State Fleming’s Right Hand Rule.
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उत्तर
- Stretch the thumb, forefinger and middle finger of the right hand so that they are perpendicular to each other.
- If the forefinger indicates the direction of the magnetic field and the thumb shows the direction of the motion of the conductor, then the middle finger will show the direction of the induced current.
- The induced current is found to be the maximum when the direction of motion of the coil is at right angles to the magnetic field.
APPEARS IN
संबंधित प्रश्न
The device used for producing electric current is called _________.
State Fleming’s right-hand rule.
Two circular coils A and B are placed closed to each other. If the current in the coil A is changed, will some current be induced in the coil B? Give reason.
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?
State the factors on which the strength of an electromagnet depends. How does it depend on these factors?
The most suitable material for making the core of an electromagnet is:
(a) soft iron
(b) brass
(c) aluminium
(d) steel
When current is 'switched on' and 'switched off' in a coil, a current is induced in another coil kept near it. What is this phenomenon known as?
Describe one experiment to demonstrate the phenomenon of electromagnetic induction.
In which of the following case does the electromagnetic induction occur?
A loop of wire is held near a magnet.
Welders wear special glass goggles while working. Why? Explain.
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(a) `1/(RC)`
(b) `R/L`
(c) `1/sqrt(LC)`
(d) C/L
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(a) The charge on C just after t = 0 is εC.
(b) The charge on C long after t = 0 is εC.
(c) The current in L just before t = t0 is ε/R.
(d) The current in L long after t = t0 is ε/R.
Draw and label the diagram of a simple D.C. motor.
(a) Explain the rotation of the coil, giving a reason for your answer.
(b) How can you reverse the direction of rotation of the armature?
(c) How can you increase the speed of rotation of the motor?
Draw a labelled diagram to show how an electromagnet is made.
List some of the practical applications of an electromagnet.
Why soft iron is preferred to be used as the core of the electromagnet of an electric bell?
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- State your observation when the current is switched on.
- Give an explanation for your observation in (i).
- State the rule, which will help you to find the motion of rotation of the coil.
- In which position will the coil ultimately come to rest?
- State four ways of increasing the magnitude of force acting on the coil.
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Using Ampere's law, obtain an expression for the magnetic induction near a current-carrying straight infinitely long wire.
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Find the odd one out and give its explanation.
Write the two names in the following diagram.
Fleming’s right hand rule.
Obtain an expression for motional emf from Lorentz force.
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An alternating emf of 0.2 V is applied across an L-C-R series circuit having R = 4Q, C = 80µF, and L = 200 mH. At resonance the voltage drop across the inductor is
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A cylindrical bar magnet is kept along the axis of a circular coil. If the magnet is rotated about its axis, then ____________.
A cylindrical bar magnet (A) and similar unmagnetized cylindrical iron bar (B) are dropped through metallic pipe. The time taken to come down by ____________.
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.
What is the principle which Ansari Sir is trying to demonstrate?
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.
What will be observed when the Magnet starts oscillating through the coil. Explain the reason behind this observation.
If the sun radiates energy at the rate of 3.6 × 1033 ergs/sec the rate at which the sun is loosing mass is given by ______.
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Which of the following phenomena makes use of electromagnetic induction?
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Which type of force is experienced by a moving charge in a magnetic field?
When an electric current is passed through a wire or a coil, a magnetic field is produced. Is the reverse phenomenon possible i.e, can a magnetic field produce an electric current? Explain with the help of an appropriate example.
