Which of the following graphs correctly represents the variation of magnetic field induction with distance due to a thin wire carrying current?
1. | 2. | ||
3. | 4. |
A circular loop with a radius of 20 cm is placed in a uniform magnetic field B = 2T in the XY plane as shown in the figure. If the loop carries a current of i = 1 A, then the magnitude of torque acting on the loop will be:
1. 0.25 N-m
2. 5.2 N-m
3. 2.5 N-m
4. 0.52 N-m
If the planes of two identical concentric coils are perpendicular and the magnetic moment of each coil is \(\mathrm M,\) then the resultant magnetic moment of the two-coil system will be:
1. | \(\mathrm M\) | 2. | \(\sqrt{2}\mathrm M\) |
3. | \(3\mathrm M\) | 4. | \(2\mathrm M\) |
When a 12 Ω resistor is connected in parallel with a moving coil galvanometer, its deflection reduces from 50 divisions to 10 divisions. What will be the resistance of the galvanometer?
1. 24 Ω
2. 36 Ω
3. 48 Ω
4. 60 Ω
Which one of the following gives the value of the magnetic field according to Biot-Savart’s law?
1. | \(\frac{\mathrm{i} \Delta \mathrm{l} \sin (\theta)}{\mathrm{r}^2} \) | 2. | \(\frac{\mu_0}{4 \pi} \frac{\mathrm{i} \Delta \mathrm{l} \sin (\theta)}{\mathrm{r}} \) |
3. | \(\frac{\mu_0}{4 \pi} \frac{\mathrm{i} \Delta \mathrm{l} \sin (\theta)}{\mathrm{r}^2} \) | 4. | \(\frac{\mu_0}{4 \pi} \mathrm{i} \Delta \mathrm{l} \sin (\theta)\) |
What is the magnetic field at point O in the figure?
1.
2.
3.
4.
What is a representation of the magnetic field caused by a straight conductor with a uniform cross-section and a steady current of radius 'a'?
1. | 2. | ||
3. | 4. |
A current-carrying wire is placed in a uniform magnetic field in the shape of the curve \(y= \alpha sin ({\pi x \over L}),~0 \underline{<}x \underline{<}~2L\)
. What will be the force acting on the wire?
1. | \(iBL \over \pi\) | 2. | \(iBL \pi\) |
3. | \(2iBL \) | 4. | Zero |
A circular coil is in the y-z plane with its centre at the origin. The coil carries a constant current. Assuming the direction of the magnetic field at x = – 25 cm to be positive, which of the following graphs shows the variation of the magnetic field along the x-axis?
1. | 2. | ||
3. | 4. |
A particle of charge +q and mass m moving under the influence of a uniform electric field and a uniform magnetic field follows a trajectory from P to Q as shown in the figure. The velocities at P and Q are and respectively. Which of the following statement(s) is/are correct?
1. | \(\mathrm{E}=\frac{3}{4} \frac{\mathrm{mv}^2}{\mathrm{qa}}\) |
2. | Rate of work done by electric field at P is\(\frac{3}{4} \frac{\mathrm{mv}^3}{\mathrm{a}}\) |
3. | Rate of work done by both fields at Q is zero |
4. | All of the above |