Cathode current

Question

The equation I = 3.4V^(3/2) gives the cathode (in milliamperes) for a particular color picture tube
as a function of voltage V (in volts). What is the cathode current when the voltage is 80 volts?

Answer 1

You are given

 

I = 3.4 V^3/2

 

Just substitute V = 80 volts into the given formula and get

 

I = 3.4 (80)^3/2 mA = 2433 mA