The core of a transformer is laminated because
The core of a transformer is laminated because
Options
(a) ratio of voltage in primary and secondary may be increased (b) energy losses due to eddy currents may be minimised (c) the weight […]
Electromagnetic Induction
The current through an inductor changes from 3 A to 2 A is 1 m/s. If induced e.m.f.
The current through an inductor changes from 3 A to 2 A is 1 m/s. If induced e.m.f. in inductor is 5V then L is
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(a) 5×10⁻² H (b) 5×10⁻³ H (c) 2.5×10⁻³ […]
Which of the following is the function of the step-up transformer?
Which of the following is the function of the step-up transformer?
Options
(a) Low voltage, high current to high voltage and low current (b) Low voltage, low current to high voltage and high […]
In an inductor when current changes from 2 A to 18 A in 0.05 sec, the e.m.f. induced
In an inductor when current changes from 2 A to 18 A in 0.05 sec, the e.m.f. induced is 20 V. The inductance L is
Options
(a) 62.5 mH (b) 625 mH (c) 6.25 […]
Energy in a current carrying coil is stored in the form of
Energy in a current carrying coil is stored in the form of
Options
(a) electrical energy (b) magnetic field (c) heat (d) None of these
Correct Answer:
magnetic field
Explanation:
In a current carrying […]
In an LCR circuit, capacitance is changed from C to 2C. For the resonant frequency
In an LCR circuit, capacitance is changed from C to 2C. For the resonant frequency to remain unchanged, the inductance should be changed from L to
Options
(a) 4 L (b) 2 L (c) […]
The material suitable for making electromagnets should have
The material suitable for making electromagnets should have
Options
(a) High retentivity and high coercivity (b) Low retentivity and low coercivity (c) high retentivity and low coercivity (d) Low retentivity and high coercivity
Radiofrequency choke uses core of
Radiofrequency choke uses core of
Options
(a) Air (b) Iron (c) Air and iron (d) None of these
Correct Answer:
Air
Explanation:
Radio frequencies are higher frequencies. Air core chokes are therefore used.
The magnetic flux linked with a circuit of resistance 100Ω increases from 10 to 60 Wb.
The magnetic flux linked with a circuit of resistance 100Ω increases from 10 to 60 Wb. The amount of induced charge that flows in the circuit is (in coulomb)
Options
(a) 0.5 (b) 5 […]
The coefficient of mutual inductance of two coils is 6 mH. If the current flowing
The coefficient of mutual inductance of two coils is 6 mH. If the current flowing in one is 2A, the induced e.m.f. in the second coil will be
Options
(a) Zero (b) 3 V […]