Assertion (A): At a temperature of 1000 K, thermionic emission current is about 0.1 A/cm2 of surface. Reason (R): Thermionic emission current is given by Ith = SA0 T2 e-Ew/kT.

• Both A and R are true and R is correct explanation of A
• Both A and R are true but R is not correct explanation of A
• A is true but R is false
• A is false but R is true