question_answer

The threshold wavelength for lithium is 5250\[\overset{\text{o}}{\mathop{\text{A}}}\,\]. For photo emission to take place, the wavelength of the incident light must be

A)  more than \[\text{525}0\overset{\text{o}}{\mathop{\text{A}}}\,\]

B)  exactly equal to \[\text{525}0\text{ }\overset{\text{o}}{\mathop{\text{A}}}\,\]

C)  equal to or more than \[\text{525}0\text{ }\overset{\text{o}}{\mathop{\text{A}}}\,\]

D)  equal to or less than \[\text{525}0\text{ }\overset{\text{o}}{\mathop{\text{A}}}\,\]