MCQ
$A$ metal have work function $4\, eV$ is exposed to photon of $\lambda = 1240\,\mathop A\limits^o $. If $a$ accelerating potential of $7.6\, volt$ is applied, then the electron with maximum kinetic energy will have speed equal to -
- ✓$2.18 × 10^6\, m/s$
- B$3 × 10^8 \,m/s$
- C$9.61 × 10^5\, m/s$
- D$8.72 × 10^6\, m/s$