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प्रश्न
Electromagnetic induction means ______.
विकल्प
Charging of an electric conductor.
Production of magnetic field due to a current flowing through a coil.
Generation of a current in a coil due to relative motion between the coil and the magnet.
Motion of the coil around the axle in an electric motor.
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उत्तर
Electromagnetic induction means generation of a current in a coil due to relative motion between the coil and the magnet.
APPEARS IN
संबंधित प्रश्न
State Fleming’s right-hand rule.
What is electromagnetic induction?
Prove theoretically (electromagnetic induction) `e = (dphi)/(dt)`
A circular coil of cross-sectional area 200 cm2 and 20 turns is rotated about the vertical diameter with angular speed of 50 rad s−1 in a uniform magnetic field of magnitude 3.0 × 10−2T. Calculate the maximum value of the current in the coil.
Name two devices in which electromagnets are used and two devices where permanent magnets are used.
What condition is necessary for the production of current by electromagnetic induction?
State whether the following statement are true or false:
A generator works on the principle of electromagnetic induction.
State whether the following statement are true or false:
A motor works on the principle electric generator?
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?
How is the working of an electric bell affected, if alternating current be used instead of direct current?
In which of the following case does the electromagnetic induction occur?
A loop of wire is held near a magnet.
Name and state the law which determines the direction of induced current.
or
State Fleming’s right-hand rule.
Welders wear special glass goggles while working. Why? Explain.
When Puja, a student of 10th class, watched her mother washing clothes in the open, she observed coloured soap bubbles and was curious to know why the soap bubbles appear coloured. In the evening when her father, an engineer by profession, came home, she asked him this question. Her father explained to her the basic phenomenon of physics due to which the soap bubbles appear coloured.
(a) What according to you are the values displayed by Puja and her father?
(b) State the phenomenon of light involved in the formation of coloured soap bubbles.
Welders wear special goggles or face masks with glass windows to protect their eyes from electromagnetic radiations. Name the radiations and write the range of their frequency.
Figure shows a long U-shaped wire of width l placed in a perpendicular magnetic field B. A wire of length l is slid on the U-shaped wire with a constant velocity v towards right. The resistance of all the wires is r per unit length. At t = 0, the sliding wire is close to the left edge of the U-shaped wire. (a) Calculate the force needed to keep the sliding wire moving with a constant velocity v. (b) If the force needed just after t = 0 is F0, find the time at which the force needed will be F0/2.0
Fill in the blanks by writing (i) Only soft iron, (ii) Only steel, (iii) Both soft-iron and steel for the material of core and/or magnet.
D.C. motor ______.
Fill in the blanks by writing (i) Only soft iron, (ii) Only steel, (iii) Both soft-iron and steel for the material of core and/or magnet.
A. C. generator______.
Fill in the blanks by writing (i) Only soft iron, (ii) Only steel, (iii) Both soft-iron and steel for the material of core and/or magnet.
Transformer______.
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.
State Fleming’s Right Hand Rule.
Answer the following:
State the principles of the electric motor and electric generator.
Choose the correct option:
A conductor rod of length (l) is moving with velocity (v) in a direction normal to a uniform magnetic field (B). What will be the magnitude of induced emf produced between the ends of the moving conductor?
Using Ampere's law, obtain an expression for the magnetic induction near a current-carrying straight infinitely long wire.
Observe the given figure of Fleming’s Right Hand Rule and write the labels of A and B correctly.
Fleming's left hand rule : electric current : : Fleming's right hand rule : _______
Establish the fact that the relative motion between the coil and the magnet induces an emf in the coil of a closed circuit.
A coil of 200 turns carries a current of 0.4 A. If the magnetic flux of 4 mWb is linked with each turn of the coil, find the inductance of the coil.
Shown in the figure below is a metre bridge set up with null deflection in the galvanometer. The value of the unknown resistance R is ______
We can induce the current in a coil by ____________.
What should be the core of an electromagnet?
Which of the following instruments works by electromagnetic induction?
For making a strong electromagnet the material of the core should be ______.
The working of a dynamo is based on the principle of
A current I = 10 sin(100π t) A is passed in first coil, which induces a maximum e.m.f of 5π volt in second coil. The mutual inductance between the coils is ______.
An expression for oscillating electric field in a plane electromagnetic wave is given as Ez = 300 sin(5π × 103x - 3π × 1011t)Vm-1 Then, the value of magnetic field amplitude will be ______. (Given: speed of light in Vacuum c = 3 × 108 ms-1)
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.
