A students connects an ammeter `A ` and a voltmeter `V` to measure a resistancer as shown in figure. If the voltmeter reads `20 V` and the ammeter reads `4A`, then `R` is

Options

A. equal to `5Omega`
B. greater than `5Omega`
C. less than `5Omega`
D. greater or less than `5Omega` depending upon the direction of current

Answer

C

Explanation

`4(R+R_A)=20V`
`:. R=5-R_A`
where `R_A`= resistane of ammeter