How does quantum theory explain the working of a photocell?

Each photon of light with a certain minimum energy releases an electron from an atom.

Explanation:

A photocell works on the principle of photoelectric effect. A proton is taken to have a particle nature hence photons have to interact with electrons.In this particular experiment, photons have energy greater than the work function of the metal and thus ejects electrons from the plate.

answer: the rock sample is a sedimentary rock.

explanation:

it is given that:

mass of rock sample, m = 2.7 g

volume of rock sample,

so, density of rock sample will be

since, the density of rock sample is . hence, the rock sample is a sedimentary rock, whose densities varies between .

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27