MCQ
An ammeter whose resistance is $180 \Omega$ gives full scale deflection when current is $2 \mathrm{~mA}$. The shunt required to convert it into an ammeter reading $20 \mathrm{~mA}$ (in ohms) is
- A$18$
- ✓$20$
- C$0.1$
- D$10$
✓
Answer
Correct option: B.
$20$
Given $i_g=2 \mathrm{~mA}, i=20 \mathrm{~mA}, G=180 \Omega$
$\frac{i_g}{i}=\frac{S}{G+S} \Rightarrow 180+S=10 S \Rightarrow S=\frac{180}{9}=20 \Omega$
$\frac{i_g}{i}=\frac{S}{G+S} \Rightarrow 180+S=10 S \Rightarrow S=\frac{180}{9}=20 \Omega$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Two identical circular loops of metal wire are lying on a table without touching each other. Loop- $A$ carries a current which increases with time. In response, the loop- $B$(CM is the centre of mass)
→In a communication system, noise is most likely to affect the signal
The specific resistance of manganin is $50 \times 10^{-8} \mathrm{ohm} \times \mathrm{m}$. The resistance of a cube of length $50 \mathrm{~cm}$ will be
→In sum and difference method in vibration magnetometer, the time period is more if
A particle falls towards earth from infinity. It's velocity on reaching the earth would be
A plumb line is suspended from a ceiling of a car moving with horizontal acceleration of $a$. What will be the angle of inclination with vertical
→The rectangular surface of area $8 \mathrm{~cm} \times 4 \mathrm{~cm}$ of a black body at a temperature of $127^{\circ} \mathrm{C}$ emits energy at the rate of $E$ per second. If the length and breadth of the surface are each reduced to half of the initial value and the temperature is raised to $327^{\circ} \mathrm{C}$, the rate of emission of energy will become
→A cylindrical tube of uniform cross-sectional area $A$ is fitted with two air tight frictionless pistons. The pistons are connected to each other by a metallic wire. Initially the pressure of the gas is $P$ and temperature is $T$, atmospheric pressure is also $P$. Now the temperature of the gas is increased to $2 T$, the tension in the wire will be
→A tennis ball is released from height $h$ above ground level. If the ball makes inelastic collision with the ground, to what height will it rise after third collision
→A body falling from a height of $10 \mathrm{~m}$ rebounds from hard floor. If it loses $20 \%$ energy in the impact, then coefficient of restitution is
→