Electric Charges and Fields — Physics STD 12 Science — Question

For a given value of n, the number of electrons in an orbit is?

A positively charged particle moving along x-axis with a certain velocity enters a uniform electric field directed along positive y-axis. Its

(a) Vertical velocity changes but horizontal velocity remains constant

(b) Horizontal velocity changes but vertical velocity remains constant

(c) Both vertical and horizontal velocities change

(d) Neither vertical nor horizontal velocity changes

The frequencies of X-rays, g-rays and ultraviolet rays are respectively a, b and c. Then

(a) a < b, b > c

(b) a > b, b > c

(c) a > b, b < c

(d) a < b, b < c

In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of:

The Sun receives its radiation energy from :

In Young's double slit experiment when wavelength used is 6000 Å and the screen is 40 cm from the slits, the fringes are 0.012 cm wide. What is the distance between the slits

(a) 0.024 cm

(b) 2.4 cm

(c) 0.24 cm

(d) 0.2 cm

A square metallic wire loop of side 0.1 m and resistance of 1W is moved with a constant velocity in a magnetic field of 2 wb/m² as shown in figure. The magnetic field is perpendicular to the plane of the loop, loop is connected to a network of resistances. What should be the velocity of loop so as to have a steady current of 1mA in loop

(a) 1 cm/sec

(b) 2 cm/sec

(c) 3 cm/sec

(d) 4 cm/sec

The capacitance of the capacitor is directly proportional to the:

A charge +Q is moving upwards vertically. It enters a magnetic field directed to the north. The force on the charge will be towards

(a) North

(b) South

(c) East

(d) West

The log-log graph between the energy E of an electron and its de-Broglie wavelength λ  will be

(a)

(a)

(c)

(d)