Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

An alternating current generator has an internal resistance R_g and an internal reactance X_g. It is used to supply power to a passive load consisting of a resistance R_g and a reactance X_L. For maximum power to be delivered from the generator to the load, the value of X_L is equal to:

To reduce the reasonant frequency in an LCR series circuit with a generator:

Assertion  :   The surface charge densities of two spherical conductors of different radii are equal. Then the electric field intensities near their surface are also equal.

Reason    : Surface charge density is equal to charge per unit area.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

Critical angle of light passing from glass to air is minimum for

(a) Red

(b) Green

(c) Yellow

(d) Violet

In a vibration magnetometer, the time period of a bar magnet oscillating in horizontal component of earth's magnetic field is 2 sec. When a magnet is brought near and parallel to it, the time period reduces to 1 sec. The ratio H/F of the horizontal component H and the field F due to magnet will be

(a) 3

(b) 1/3

(c)

(d) 1/

A concave mirror of focal length 15 cm forms an image having twice the linear dimensions of the object. The position of the object when the image is virtual will be

(a) 22.5 cm

(b) 7.5 cm

(c) 30 cm

(d) 45 cm

In the valance band, the current is due to:

If light is passed through a double-slit opening and falls onto a screen, Identify the pattern produced on the screen.

Arrange the following in the increasing order of magnetic susceptibility.