A non-zero current passes through the galvanometer G shown in the circuit when the key 'K' is closed and its value does not change when the key is opened. Then which of the following statements (s) is/are true?

Options

A. The galvanometer resistance is infinite.
B. The current through the galvanometer is 40 mA.
C. After the key is closed, the current through the 200 `Omega` resistor is same as the current through the 300 `Omega` resistor.
D. The galvanometer resistance is 150 `Omega`

Answer

B, C, D

Explanation

It is a case of balanced wheatstone bridge
` therefore (200)/(300) = (100)/( G) implies G = 150 Omega `

` R_(eq) = ( 500 xx 250 ) /( 750) = (500)/(3) Omega `
Now current through galvanometer
`I^- = (10)/( 250) =(1)/(25) = 0.04 A = 40 m A `
After key is closed wheatstone bridge condition is applied and since `200 Omega` and `300 Omega ` are in series therefore current through both will be the same .