In an X-rays tube, if the electrons are accelerated through 140 KV, then anode current obtained is 30 mA. If the whole energy of electrons is converted into heat, then the rate of production of heat at anode will be :

Options

A. 968 calorie
B. 892 calorie
C. 1000 calorie
D. 286 calorie.

Answer

C

Explanation

Because `P=(Q)/(t)=(W)/(t)=VI,Q` is heat produced.
`P=140xx10^(3)xx30xx10^(-3)`
`=4200` watt=4200 Joule/sec
or `P=(4200)/(4*2)=1000` calorie.