Nuclei — Physics STD 12 Science — Question

A large nonconducting sheet M is given a uniform charge density. Two uncharged small metal rods A and B are placed near the sheet as shown in figure:

In an interference experiment, third bright fringe is obtained at a point on the screen with a light of 700 nm. What should be the wavelength of the light source in order to obtain 5th bright fringe at the same point

(a) 500 nm

(b) 630 nm

(c) 750 nm

(d) 420 nm

The photo-electrons emitted from a surface of sodium metal are such that        

(a) They all are of the same frequency

(b) They have the same kinetic energy

(c) They have the same de Broglie wavelength

(d) They have their speeds varying from zero to a certain maximum

A proton, a neutron, an electron and an particle have same energy. Then their de Broglie wavelengths compare as:

A 60 watt bulb is hung over the center of a table 4 m × 4 m at a height of 3 m. The ratio of the intensities of illumination at a point on the centre of the edge and on the corner of the table is

(a)

(b) 2 / 1

(c) 17 / 13

(d)  5 / 4

Two identical conductors of copper and aluminium are placed in an identical electric fields. The magnitude of induced charge in the aluminium will be

(a) Zero	(b) Greater than in copper
(c) Equal to that in copper	(d) Less than in copper

The focal length of a concave mirror is 50 cm. Where an object be placed so that its image is two times and inverted

(a) 75 cm

(b) 72 cm

(c) 63 cm

(d) 50 cm

Nuclear fusion reactions cannot be harnessed for productive applications because:

________  represents the most significant digits of the resistance value in finding the  resistance of carbon resistor.

The minimum wavelength of the X-rays produced by electrons accelerated through a potential difference of V volts is directly proportional to

(a)

(b)

(c) 1/

(d) 1/V