Nuclei — Physics STD 12 Science — Question

The state of photo-electrons emerging from the metal surface can be :

An electron passing through a potential difference of 4.9 V collides with a mercury atom and transfers it to the first excited state. What is the wavelength of a photon corresponding to the transition of the mercury atom to its normal state

(a) 2050 Å

(b) 2240 Å

(c) 2525 Å

(d) 2935 Å

What is shape of magnet in moving coil galvanometer to make the radial magnetic field?

 has half life 5700 years. At the end of 11400 years, the actual amount left is

(a) 0.5 of original amount	(b) 0.25 of original amount
(c) 0.125 of original amount	(d) 0.0625 of original amount

Lorentz force is given by the formula:

Photons are deflected by:

If 64 charged drops of water are mixed to form one big drop, then how many times the value of potential on the big drop will be from the full value?

The plates of a parallel plate condenser are pulled apart with a velocity v. If at any instant their mutual distance of separation is d, then the magnitude of the time of rate of change of capacity depends on d as follows

(a)

(b)

(c)

(d) d

Consider the junction diode as ideal. The value of current flowing through AB is 

A photon of energy 3.4 eV is incident on a metal having work function 2 eV. The maximum K.E. of photo-electrons is equal to

(a) 1.4 eV

(b) 1.7 eV

(c) 5.4 eV

(d) 6.8 eV