Assertion : Photosensitivity of a metal is high if its work function is small.
Reason : Work function = ${\mathrm{hf}}_0$ where ${\mathrm{f}}_0$ is the threshold frequency

1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
3. If the assertion is true but the reason is false
4. If both the assertion and reason are false

Assertion : The de-Broglie wavelength of a molecule varies inversely as the square root of temperature.
Reason : The root mean square velocity of the molecule depends on the temperature.

Assertion : The specific charge for positive rays is a characteristic constant.
Reason : The specific charge depends on charge and mass of positive ions present in positive rays.

Assertion : In photoelectric effect, on increasing the intensity of light, both the number of electrons emitted and kinetic energy of each of them get increased but photoelectric current remains unchanged.
Reason : The photoelectric current depends only on wavelength of light.

Assertion : The threshold frequency of photoelectric effect supports the particle nature of sunlight.
Reason : If frequency of incident light is less than the threshold frequency, electrons are not emitted from metal surface.

Assertion : In photoemissive cell inert gas is used.
Reason : Inert gas in the photoemissive cell gives greater current.

Assertion : The specific charge of positive rays is not constant.
Reason : The mass of ions varies with speed.

Assertion : Mass of moving photon varies inversely as the wavelength.
Reason : Energy of the particle  = Mass$\times {\left(\mathrm{speed} \mathrm{of} \mathrm{light}\right)}^2$

Assertion : When the speed of an electron increases its specific charge decreases.
Reason : Specific charge is the ratio of the charge to mass.

Assertion : Photoelectric effect demonstrates the wave nature of light.
Reason : The number of photoelectrons is proportional to the frequency of light.