Physics Quarter-4

Which of the following electromagnetic radiations has photons with the greatest momentum?

• Blue light

• Yellow light

• X rays

• Radio waves

Possible units for the disintegration constant λ are:

• kg/s

• hour

• s/kg

• day⁻¹

To achieve DC from AC, AC will be applied across

• AC

• BD

• AB

• DC

Work function is

• energy necessary to eject the electron from its orbit

• energy necessary to eject an electron from within a metal body

• minimum necessary energy to eject an electron from a metal surface

• wavelength necessary for releasing an electron from a body

If the velocity of electron entering in velocity selector is V < E/B , the electron will

• Move straight

• Move in circular path

In a half wave rectifier, the frequency of the input is N, the frequency and form of the output will be

• N/2 and Pulsating

• 2N and steady

• N and Pulsating

• N and continuous

When a photon collides with an electron which of the following of photon increases?

• Frequency

• Energy

• Wavelength

• None

Activity of a sample is initially 320 counts per second. At the end of 90 minutes it gives 40 counts per second. What is the half-life of the element in sample?

• 30 minutes

• 60 minutes

• 45 minutes

• 75 minutes

The emission of β-particle from polonium-218 results in the formation of

• Protactinium-143

• Astatine-218

• Radon -222 gas

• Thorium-234

Paschen series is obtained when all the transitions of electron terminate on.

• 2^nd orbit

• 3^rd orbit

• 4^th orbit

• 5^th orbit