PHYSICS for Joint Entrance Examination JEE (Advanced) Electrostatics and Current Electricity>Chapter 6 - Electrical Measuring Instruments>Archives>Q 1

HARD

JEE Advanced

IMPORTANT

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Consider two identical galvanometers and two identical resistors with resistance $R$ . If the internal resistance of the galvanometers $R_{C} < R / 2$ , which of the following statement(s) about any one of the galvanometers is (are) true?

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Important Questions on Electrical Measuring Instruments

HARD

JEE Advanced

IMPORTANT

PHYSICS for Joint Entrance Examination JEE (Advanced) Electrostatics and Current Electricity>Chapter 6 - Electrical Measuring Instruments>Archives>Q 1

A galvanometer gives full scale deflection with

0.006 A

current. By connecting it to a

4990 Ω

resistance, it can be converted into a voltmeter of range

0 - 30 V

. If connected to a

\frac{2 n}{249} Ω

resistance, it becomes an ammeter of range

0 - 1.5 A

. The value of

n

is,

HARD

JEE Advanced

IMPORTANT

PHYSICS for Joint Entrance Examination JEE (Advanced) Electrostatics and Current Electricity>Chapter 6 - Electrical Measuring Instruments>Archives>Q 2

A moving coil galvanometer has

50

turns and each turn has an area of

2 \times 10^{- 4} m^{2}

. The magnetic field produced by the magnet inside the galvanometer is

0.02 T

. The torsional constant of the suspension wire is

10^{- 4} N m {rad}^{- 1}

. When a current flows through the galvanometer, a full-scale deflection occurs if the coil rotates by

0.2 rad

. The resistance of the coil of the galvanometer is

50 Ω

. This galvanometer is to be converted into an ammeter capable of measuring current in the range

0 - 1.0 A

. For this purpose, a shunt resistance is to be added in parallel to the galvanometer. The value of this shunt resistance, in ohms, is,