Ray Optics and Optical Instruments — Physics STD 12 Science — Question

A conducting resistor is joined with a battery. If the temperature of the conductor is changed with the cooling process, then the magnitude of current flowing:

A rectangular coil 20 cm × 20 cm  has 100 turns and carries a current of 1 A. It is placed in a uniform magnetic field       B  = 0.5 T with the direction of magnetic field parallel to the plane of the coil. The magnitude of the torque required to hold this coil in this position is(a) Zero  (b) 200 N-m(c) 2 N-m  (d) 10 N-m

Electrostatic potential is ______ throughout the volume of the conductor and has _____ value on its surface.

The bottom of a container filled with liquid appear slightly raised because of(a) Refraction(b) Interference(c) Diffraction(d) Reflection

Two current carrying loops of same area but of different materials have same current flowing in them in anti-clockwise direction. if a magnetic field is applied in upward direction then potential energy of loop 1 and loop 2 will always be:

Which of the following series in the spectrum of hydrogen atom lies in the visible region of the electromagnetic spectrum?

The electric resistance of a certain wire of iron is R. If its length and radius are both doubled, then(a) The resistance will be doubled and the specific resistance will be halved(b) The resistance will be halved and the specific resistance will remain unchanged(c) The resistance will be halved and the specific resistance will be doubled(d) The resistance and the specific resistance, will both remain unchanged

A magnetic field can be produced by :