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प्रश्न
State three ways in which the strength of an electromagnet can be increased.
उत्तर
Strength of an electromagnet can be increased in the following three ways:
1. By increasing the number of turns in the coil of the electromagnet
2. By increasing the flow of current in the coil of the electromagnet
3. By reducing the length of air gap between the poles of the electromagnet
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संबंधित प्रश्न
Name a common device that uses electromagnets.
Describe different ways to induce current in a coil of wire.
L, C and R represent the physical quantities inductance, capacitance and resistance respectively. Which of the following combinations have dimensions of frequency?
(a) `1/(RC)`
(b) `R/L`
(c) `1/sqrt(LC)`
(d) C/L
The switches in figure (a) and (b) are closed at t = 0 and reopened after a long time at t = t0.
(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.
Answer the following:
State the principles of the electric motor and electric generator.
Find the odd one out and give its explanation.
A cylindrical bar magnet (A) and similar unmagnetized cylindrical iron bar (B) are dropped through metallic pipe. The time taken to come down by ____________.
One solenoid is centered inside another. The outer one has a length of 50.0 cm and contains 6750 coils, while the coaxial inner solenoid is 3.0 cm long and π cm2 in area and contains 150 coils. The current in the outer solenoid is changing at 3000 A/s. The emf induced in the inner solenoid is ______ V.
(Round off to two decimal places.)
The charge will flow through a galvanometer of resistance 200Ω connected to a 400Ω circular coil of 1000 turns wound on a wooden stick 20 mm in diameter, if a magnetic field B = 0.012 T parallel to the axis of the stick decreased suddenly to zero, is near ______.
