Assertion :Potassium and caesium are useful as electrodes in photoelectric cells. Reason: Potassium and caesium, when irradiated with light, the light energy absorbed is sufficient to eject out the electron from an atom.

Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Assertion is correct but Reason is incorrect

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Assertion is incorrect but Reason is correct

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
Potassium and caesium have low ionisation energies and, therefore, their valence shell electrons can be easily ejected out by the energy of light. So potassium and caesium can be used as electrodes in photoelectric cells.

Hence, option $A$ is correct.

Suggest Corrections

Similar questions

Q. Assertion: The compressibility factor for

H_{2}

and

H e

(1 + \frac{P b}{R T})

Reason: The compressibility factor for

H_{2}

and

H e

can be derived from Van der Waal's equation.

Q. Assertion : Two electrons of helium atom are placed in only one shell but three electrons of lithium need two shells.
Reason: A shell can have maximum

{2n}^{2}

electrons.

Assertion (A) All collision of reactant molecules lead to product formation.

Reason (R) Only those collisions in which molecules have correct orientation and sufficient kinetic energy lead to compound formation.

(a) Both assertion and reason are correct and the reason is correct explanation of assertion
(b) Both assertion and reason are correct, but reason does not explain assertion.
(c) Assertion is correct, but reason is incorrect
(d) Both assertion and reason are incorrect
(e) Assertion is incorrect but reason is correct.

Q. Assertion: The impurities such as

{SiO}_{2}

present in iron ore is removed by

{CaCO}_{3}

.

Reason:

CaO

formed by decomposition of

{CaCO}_{3}

reacts with

{SiO}_{2}

to form slag.

Assertion – The non-fusible impurities present in iron ore are removed by $C a C O_{3}$ .

Reason: $C a C O_{3}$ which decomposes into $C a O$ and $C O_{2}$ . The $C a O$ formed reacts with $S i O_{2}$ to remove silica

Join BYJU'S Learning Program