Q. No.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. \(0.20~\text{T}\)
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. | \(5.4\times 10^{-8}~\mathrm{T}\) |
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 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 |
(I) \(a\)
(II) \(1\over a\)
(III) \(n\)
(IV) \(i\)
1. I, III, IV
2. II, III, IV
3. III, IV
4. IV Only
In both cases, the torque on P due to Q is zero. If P is slightly rotated about a diameter, then, it will return to its initial position in:
| 1. | case (I) but not in case (II). |
| 2. | case (II) but not in case (I). |
| 3. | both cases (I) and (II). |
| 4. | neither of cases (I) and (II). |
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