When will the current sensitivity of a moving coil galvanometer be high?
(N = number of turns, B = magnetic field, A = area of coil, and C = Torsional constant of spring)
1. | N is small | 2. | B is small |
3. | A is small | 4. | C is small |
A rectangular loop carrying a current \(\mathrm{I_1}\), is situated near a long straight wire carrying a steady current \(\mathrm{I_2}\).
If the wire is parallel to one of the sides of the loop and is in the plane of the loop as shown in the figure, then the current loop will:
1. | move away from the wire. |
2. | move towards the wire. |
3. | remain stationary. |
4. | rotate about an axis parallel to the wire. |
A milliammeter of 10 mA has a coil resistance of 1 Ω. To use it as an ammeter of range 1 A, the required shunt must have a resistance of:
1. \(\frac{1}{101}~\Omega \)
2. \(\frac{1}{100}~\Omega \)
3. \(\frac{1}{99}~\Omega \)
4. \(\frac{1}{9}~\Omega \)
Two toroids \(1\) and \(2\) have total no. of turns \(200\) and \(100\) respectively with average radii \(40~\text{cm}\) and \(20~\text{cm}\) respectively. If they carry the same current \(i\), what will be the ratio of the magnetic fields along the two loops?
1. \(1:1\)
2. \(4:1\)
3. \(2:1\)
4. \(1:2\)
Three infinitely-long conductors carrying currents lie perpendicular to the plane of the paper as shown below.
If the value of integral for the loops in the units of N/A, respectively, then:
1. | \(I_1=3 A\) into the paper | 2. | \(I_2=3 A\) out of the paper |
3. | \(I_3=0\) | 4. | \(I_3=1 A\) out of the paper |
A ring of radius R carries a linear charge density . It is rotating with angular speed about an axis passing through the centre and perpendicular to the plane. What is the magnetic field at its centre?
1.
2.
3.
4.
The figure depicts a cross-section of a large metal sheet with an electric current flowing along its surface. The current in a dl-width strip is (Kdl), where K is a constant. What is the magnetic field at a point P and at a distance x from the metal strips?
1.
2.
3.
4.
1. 0.25 amp
2. 0.8 amp
3. 0.2 amp
4. 0.5 amp
The current sensitivity of a moving coil galvanometer is 5 div/mA and its voltage sensitivity (angular deflection per unit voltage applied) is 20 div/V. How much is the resistance of the galvanometer?
1. | \(40~ \Omega\) | 2. | \(25~ \Omega\) |
3. | \(250~ \Omega\) | 4. | \(500~ \Omega\) |
Perpendicularly, an electron and a proton enter a magnetic field. Both have the same amount of kinetic energy. Which of the following statements is correct?
1. | Trajectory of electron is less curved |
2. | Trajectory of proton is less curved |
3. | Both trajectories are equally curved |
4. | Both move on a straight-line path |