Question

The maximum velocity of an electron emitted by light of wavelength l incident on the surface of a metal of work function W is –

• A. $\left\lbrack \frac{2(hc + \lambda W)}{m\lambda} \right\rbrack^{1/2}$
• B. $\frac{2(hc–\lambda W)}{m}$
• C. $\left\lbrack \frac{2(hc–\lambda W)}{m\lambda} \right\rbrack^{1/2}$
• D. $\left\lbrack \frac{2(h\lambda –W)}{m} \right\rbrack^{1/2}$

Answer 1

Answer: (C)

$\left\lbrack \frac{2(hc–\lambda W)}{m\lambda} \right\rbrack^{1/2}$

Answer 2

= W + $\frac { 1 } { 2 }$ mv²

$\frac { 1 } { 2 }$ mv² = $\frac { \mathrm { hc } } { \lambda }$ – W

$\frac { 1 } { 2 }$ mv² =

v² = 2 $\frac { ( \mathrm { hc } - \mathrm { W } \lambda ) } { \mathrm { m } \lambda }$

v =