MCQ
Alternating current can not be measured by dc ammeter because
- A$ac$ cannot pass through dc ammeter
- ✓Average value of complete cycle is zero
- C$D.C.$ ammeter will get damaged.
- D$ac$ changes its direction
✓
Answer
Correct option: B.
Average value of complete cycle is zero
b
(b)In $d$c ammeter, a coil is free to rotate in the magnetic field of a fixed magnet.
If an alternating current is passed through such a coil, the torque will reverse it’s direction each time the current changes direction and the average value of the torque will be zero.
(b)In $d$c ammeter, a coil is free to rotate in the magnetic field of a fixed magnet.
If an alternating current is passed through such a coil, the torque will reverse it’s direction each time the current changes direction and the average value of the torque will be zero.
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
Particle $A$ is moving along $x$-axis. At time $t=0$, it has velocity of $10\,m / s$ and acceleration $-4\,m / s ^2$. Particle $B$ has velocity of $20\,m / s$ and acceleration $-2\,m / s ^2$. Initially, both the particles are at origin. At time $t=2\,s$, distance between the two particles is $.............\,m$
→If the lattice constant of this semiconductor is decreased, then which of the following is correct?
$\vec{A}$ is a vector of magnitude $2.7$ units due east. What is the magnitude and direction of vector $4 \vec{A}$ ?
→A current $I$ flowing through the loop as shown in the adjoining figure. The magnetic field at centre $O$ is
→The change in the magnitude of the volume of an ideal gas when a small additional pressure $\Delta P$ is applied at a constant temperature, is the same as the change when the temperature is reduced by a small quantity $\Delta T$ at constant pressure. The initial temperature and pressure of the gas were $300\, K$ and $2\; atm$ respectively. If $|\Delta T|=C|\Delta P|$ then value of $C$ in $(K / a t m)$ is......
→The speed of a projectile at its maximum height is half of its intial speed. The angle of projection is $......... ^\circ$
→A sample of an ideal gas is taken through a cycle a shown in figure. It absorbs $50J$ of energy during the process $AB$, no heat during $BC$, rejects $70J$ during $CA.$ $40J$ of work is done on the gas during $BC$. Internal energy of gas at $A$ is $1500J$, the internal energy at $C$ would be ........ $J$
→A simple pendulum having length $\ell $ is having speed $\sqrt {2g\ell }$ at bottom most point of its trajectory. Its motion will be
→A wheel is rotating at $900\ r.p.m.$ about its axis. When the power is cut-off, it comes to rest in $1 \,minute.$ The angular retardation in $radian$/$s^2$ is
→Two similar conducting balls having charges $+q$ and $-q$ are placed at a separation $d$ from each other in air. The radius of each ball is $r$ and the separation between their centres is $d(d > > r)$. Calculate the capacitance of the two ball system
→