- AInduced EMF
- BElectric Field
- CMagnetic Field
- DMagnetic Dipole
Explanation:
A changing electric field gives rise to a magnetic field.
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The approximate wavelength of a photon of energy 2.48 eV is
|
(a) 500 Å |
(b) 5000 Å |
(c) 2000 Å |
(d) 1000 Å |
In a region of uniform magnetic induction
, a circular coil of radius 30 cm and resistance
ohm is rotated about an axis which is perpendicular to the direction of B and which forms a diameter of the coil. If the coil rotates at 200 rpm the amplitude of the alternating current induced in the coil is
|
(a) |
(b) 30 mA |
(c) 6 mA |
(d) 200 mA |
Fraunhofer lines of the solar system is an example of
|
(a) Emission spectrum |
(b) Emission band spectrum |
|
(c) Continuous emission spectrum |
(d) Line absorption spectrum |
A lens (focal length 50 cm) forms the image of a distant object which subtends an angle of 1 milliradian at the lens. What is the size of the image
|
(a) 5 mm |
(b) 1 mm |
(c) 0.5 mm |
(d) 0.1 mm |
Two wires of same length are shaped into a square and a circle. If they carry same current, ratio of the magnetic moment is
|
(a) 2 : π |
(b) π : 2 |
(c) π : 4 |
(d) 4 : π |
The sum of the reciprocals of object distance and image distance is equal to the __________ of a mirror.
In a Young's experiment, two coherent sources are placed 0.90 mm apart and the fringes are observed one metre away. If it produces the second dark fringe at a distance of 1 mm from the central fringe, the wavelength of monochromatic light used would be
|
(a) 60 |
(b) 10 |
(c) 10 |
(d) 6 |
A piece of wire of resistance 4 ohms is bent through 180° at its mid point and the two halves are twisted together, then the resistance is
|
(a) 8 ohms |
(b) 1 ohm |
(c) 2 ohms |
(d) 5 ohms |
Three positive charges of equal value q are placed at the vertices of an equilateral triangle. The resulting lines of force should be sketched as in
|
(a) |
(b) |
(c) |
(d) |