Estimate the speed with which electrons emitted from a heated emitter of an evacuated tube impinge on the collector maintained at a potential difference of 500 V with respect to the emitter. Ignore the small initial speeds of the electrons. The specific charge of the electron, i.e., its e/m is given to be 1.76 × 10^{11} C kg^{−1}.

Advertisement Remove all ads

#### Solution

Potential difference across the evacuated tube, *V* = 500 V

Specific charge of an electron, *e/m* = 1.76 × 10^{11} C kg^{−1}

The speed of each emitted electron is given by the relation for kinetic energy as:

`KE = 1/2 mv^2 = eV`

`:. v = ((2eV)/m)^(1/2) = (2V xx e/m)^(1/2)`

`= (2 xx 500 xx 1.76 xx 10^11)^(1/2) = 1.327 xx 10^ "m/s"`

Therefore, the speed of each emitted electron is `1.327 xx 10^7 "m/s"`

Is there an error in this question or solution?

Advertisement Remove all ads

#### APPEARS IN

Advertisement Remove all ads

Advertisement Remove all ads