Q. No.
A galvanometer of resistance \(50~\Omega\) is connected to a battery of \(3\) V along with a resistance of \(2950~\Omega\) in series. A full-scale deflection of \(30\) divisions is obtained in the galvanometer. In order to reduce its deflection to \(20\) divisions, the resistance added in series should be:
1. \(1050~ \Omega\)
2. \(1550~ \Omega\)
3. \(2050~ \Omega\)
4. \(1500~ \Omega\)
1. \(1050~ \Omega\)
2. \(1550~ \Omega\)
3. \(2050~ \Omega\)
4. \(1500~ \Omega\)
An arrangement of three parallel straight wires placed perpendicular to the plane of paper carrying the same current in the same direction is shown in the figure. The magnitude of force per unit length on the middle wire \(B\) is given by:
| 1. | \(\frac{\mu_0i^2}{2\pi d}\) | 2. | \(\frac{2\mu_0i^2}{\pi d}\) |
| 3. | \(\frac{\sqrt{2}\mu_0i^2}{\pi d}\) | 4. | \(\frac{\mu_0i^2}{\sqrt{2}\pi d}\) |
Resistance of a Galvanometer coil is \(8~\Omega\) and \(2~\Omega\) shunt resistance is connected with it. If main current is \(1\) A then the current flow through \(2~\Omega\) resistance will be:
1. \(0.2\) A
2. \(0.8\) A
3. \(0.1\) A
4. \(0.4\) A
A straight wire of mass \(200~\text{g}\) and length \(1.5~\text{m}\) carries a current of \(2~\text{A}\). It is suspended in mid-air by a uniform horizontal magnetic field \(B\) (shown in the figure). What is the magnitude of the magnetic field?
1. \(0.65~\text{T}\)
2. \(0.77~\text{T}\)
3. \(0.44~\text{T}\)
4. \(0.20~\text{T}\)
An element \(\Delta l=\Delta x \hat{i}\) is placed at the origin and carries a large current of \(I=10\) A (as shown in the figure). What is the magnetic field on the y-axis at a distance of \(0.5\) m?(\(\Delta x=1~\mathrm{cm}\))
| 1. | \(6\times 10^{-8}~\mathrm{T}\) | 2. | \(4\times 10^{-8}~\mathrm{T}\) |
| 3. | \(5\times 10^{-8}~\mathrm{T}\) | 4. | \(5.4\times 10^{-8}~\mathrm{T}\) |
A wire carrying a current \(I_o\) oriented along the vector \(\big(3\widehat{i}+4\widehat{j}\big)\) experiences a force per unit length of \(\big(4F\widehat{i}-3F\widehat{j}-F\widehat{k}\big)\). The magnetic field \(\overrightarrow{B}\) equals:
1. \(\frac{F}{I_o}\big(\widehat{i}+\widehat{j}\big)\)
2. \(\frac{5F}{I_o}\big(\widehat{i}+\widehat{j}+\widehat{k}\big)\)
3. \(\frac{F}{I_o}\big(\widehat{i}+\widehat{j}+\widehat{k}\big)\)
4. \(\frac{5F}{I_o}\widehat{k}\)
| 1. | it does not get overheated. |
| 2. | it does not draw excessive current. |
| 3. | it can measure large potential differences. |
| 4. | it does not appreciably change the potential difference to be measured. |
A circular loop of area \(1\) cm2, carrying a current of \(10\) A, is placed in a magnetic field of \(0.1\) T perpendicular to the plane of the loop. The torque on the loop due to the magnetic field is:
1. zero
2. \(10^{-4}\) N-m
3. \(10^{-2}\) N-m
4. \(1\) N-m
A charged particle moves in a gravity-free space without change in velocity. Which of the following is/are possible?
| a. | \(E=0,~B=0\) |
| b. | \(E=0,~B\neq0\) |
| c. | \(E\neq0,~B=0\) |
| d. | \(E\neq0,~B\neq0\) |
Choose the correct option:
| 1. | (a), (b), (d) |
| 2. | (b), (c), (a) |
| 3. | (c), (d), (b) |
| 4. | (a), (c), (d) |
A proton beam is going from north to south and an electron beam is going from south to north. Neglecting the earth's magnetic field, the electron beam will be deflected:
| 1. | towards the proton beam |
| 2. | away from the proton beam |
| 3. | upwards |
| 4. | downwards |
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