JEE Main · 2026 · 24 Jan 2026 · Shift 2 · Current Electricity

WhatsApp Email

A moving coil galvanometer of resistance 100 Ω shows a full scale deflection for a current of 1 mA. The value of resistance required to convert this galvanometer into an ammeter, showing full scale deflection for a current of 5 mA, is ____ Ω

(A)25✓ Correct
(B)10
(C)0.5
(D)2.5

Answer: (A)

Solution

To read a larger current the galvanometer is shunted so that the full-scale current

i_{g}

still passes through its coil while the excess bypasses it. The shunt resistance is

S = \frac{i _{g} G}{i - i _{g}} = \frac{( 1 mA ) ( 100 )}{( 5 - 1 ) mA} = \frac{100}{4} = 25 Ω

. The required resistance is

25 Ω

JEE Main · 2026 · 24 Jan 2026 · Shift 2 · Single correct option

Practise more: all JEE Main PYQs on Current Electricity →

More JEE Main questions on Current Electricity

A meter bridge with two resistances $R_{1}$ and $R_{2}$ as shown in figure was balanced (null point) at 40 cm from the point P. The null point changed to 50 cm from the point P, when $16Ω$ resistance is connected in parallel to $R_{2}$ . The values of resistances $R_{1}$ and $R_{2}$ ar …
JEE Main 2026View solution →
An electric power line having total resistance of $2Ω$ , delivers 1 kW of power of 250 V. The percentage efficiency of transmission line is $____$ .
JEE Main 2026View solution →
A cylindrical conductor of length 2 m and area of cross-section $0.2 mm^{2}$ carries an electric current of 1.6 A when its ends are connected to a 2 V battery. Mobility of electrons in the conductor is $α \times 1 0^{- 3} m^{2} / V$ .s. The value of …
JEE Main 2026View solution →
The charge stored by the capacitor C in the given circuit in the steady state is $____$ $μ C$ .
JEE Main 2026View solution →
The total length of potentiometer wire AB is 50 cm in the arrangement as shown in figure. If P is the point where the galvanometer shows zero reading then the length AP is $____$ cm .
JEE Main 2026View solution →
A battery with EMF E and internal resistance $r$ is connected across a resistance $R$ . The power consumption in R will be maximum when :
JEE Main 2026View solution →