A $100$ $turns$ coil shown in figure carries a current of $2\, amp$ in a magnetic field $B = 0.2\,Wb/{m^2}$. The torque acting on the coil is
A$0.32\, Nm$ tending to rotate the side $AD$ out of the page
B$0.32\, Nm$ tending to rotate the side $AD $ into the page
C$0.0032\, Nm$ tending to rotate the side $AD$ out of the page
D$0.0032\, Nm$ tending to rotate the side $AD$ into the page
Medium
Download our app for free and get started
A$0.32\, Nm$ tending to rotate the side $AD$ out of the page
a (a) $\tau = NBiA = 100 \times 0.2 \times 2 \times \left( {0.08 \times 0.1} \right) = 0.32\,N \times m$
Direction can be found by Fleming's left hand rule.
Download our app
and get started for free
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
An infinitely long wire, located on the $z$-axis, carries a current $/$ along the $+z$-direction and produces the magnetic field $\vec{B}$. The magnitude of the line integral $\int \vec{B} \cdot d l$ along a straight line from the point $(-\sqrt{3} a, a, 0)$ to $(a, a, 0)$ is given by [ $\mu_0$ is the magnetic permeability of free space.]
Two parallel wires of length $9\, m$ each are separated by a distance $0.15\, m$. If they carry equal currents in the same direction and exerts a total force of $30 \times 10^{-7} \,N$ on each other, then the value of current must be........$amp$
A non conducting ring (of mass $m,$ radius $r,$ having charge $Q$) is placed on a rough horizontal surface (in a region with transverse magnetic field). The field is increasing with time at the rate $R$ and coefficient of friction between the surface and the ring is $\mu .$ For ring to remain in equilibrium $\mu$ should be greater than
A proton is accelerating in a cyclotron where the applied magnetic field is $2 \,T$. If the potential gap is effectively $100 \,kV$ then how much revolutions the proton has to make between the "dees" to acquire a kinetic energy of $20 \,MeV$ ?
A galvanometer having a resistance $G$ and current $I_g$ flowing in it, produces full scale defection. If $S_1$ is the value of shunt which converts it into an ammeter of range $0-I$ and $S_2$ is the value of shunt for range $0-8I$ . Then the ratio $\frac {S_1}{S_2}$ will be
An electron, a proton and an alpha particle having the same kinetic energy are moving in circular orbits of radii $r_e,r_p$ and ${r_\alpha }$ respectively in a uniform magnetic field $B$. The relation between $r_e,r_p$ and $\;{r_\alpha }$ is
A conductor of length $l$ and mass $m$ is placed along the east-west line on a table. Suddenly a certain amount of charge is passed through it and it is found to jump to a height $h$. The earth’s magnetic induction is $B$. The charge passed through the conductor is:
A $50\,\Omega $ resistance is connected to a battery of $5\,V$. A galvanometer of resistance $100\, \Omega $ is to be used as an ammeter to measure current through the resistance, for this a resistance $r_s$ is connected to the galvanometer. Which of the following connections should be employed if the measured current is within $1\% $ of the current without the ammeter in the circuit ?
A circular coil has moment of inertia $0.8 \,kg m ^{2}$ around any diameter and is carrying current to roduce a magnetic moment of $20\, Am ^{2}$. The coil is kept initially in a vertical position and it can rotate freely around a horizontal diameter. When a uniform magnetic field of $4\, T$ is applied along the vertical, it starts rotating around its horizontal diameter. The angular speed the coil acquires after rotating by $60^{\circ}$ will be
The number of turns of the coil of a moving coil galvanometer is increased in order to increase current sensitivity by $50 \%$. The percentage change in voltage sensitivity of the galvanometer will be $..........\%$