1. | can be in equilibrium in one orientation. |
2. | can be in equilibrium in two orientations, both the equilibrium states are unstable. |
3. | can be in equilibrium in two orientations, one stable while the other is unstable. |
4. | experiences a torque whether the field is uniform or non-uniform in all orientations. |
When a proton is released from rest in a room, it starts with an initial acceleration a0 towards the east. When it is projected towards the north with a speed of v0, it moves with an initial acceleration of 3a0 towards the east. What are the electric and magnetic fields in the room?
1. | \(\frac{M a_0}{e} \text { west, } \frac{M a_0}{e v_0} u p\) |
2. | \(\frac{M a_0}{e} \text { west, } \frac{2 M a_0}{e v_0} \text { down }\) |
3. | \(\frac{M a_0}{e} \text { east, } \frac{2 M a_0}{e v_0} u p\) |
4. | \(\frac{M a_0}{e} \text { east, } \frac{3 M a_0}{e v_0} \text { down }\) |
Two similar coils of radius \(R\) are lying concentrically with their planes at right angles to each other. The currents flowing in them are \(I\) and \(2I,\) respectively.
What will be the resultant magnetic field induction at the centre?
1. \(\sqrt{5} \mu_0I \over 2R\)
2. \({3} \mu_0I \over 2R\)
3. \( \mu_0I \over 2R\)
4. \( \mu_0I \over R\)
A millivoltmeter of 25 mV range is to be converted into an ammeter of 25 A range. The value (in ohm) of the necessary shunt will be:
1. 0.001
2. 0.01
3. 1
4. 0.05
A current-carrying closed loop in the form of a right isosceles triangle ABC is placed in a uniform magnetic field acting along with AB.
If the magnetic force on the arm BC is F, then what is the force on the arm AC?
1. | -F | 2. | F |
3. | 2F | 4. | -2F |
A uniform electric field and a uniform magnetic field are acting in the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electron:
1. speed will decrease
2. speed will increase
3. will turn towards the left of the direction of motion
4. will turn towards the right of the direction of motion
A beam of cathode rays is subjected to cross Electric (E) and magnetic fields(B). The fields are adjusted such that the beam is not deflected. The specific charge of the cathode rays is given by:
1.
2.
3.
4.
(where V is the potential difference between cathode and anode)
A galvanometer has a coil resistance of 100 Ω and gives a full-scale deflection for 30 mA of current. If it is to work as a voltmeter in the 30 V range, how much resistance does it require to be added?
1. 900
2. 1800
3. 500
4. 1000
A square current-carrying loop is suspended in a uniform magnetic field acting in the plane of the loop. If the force on one arm of the loop is \( \overrightarrow{F}\), what will be the net force on the remaining three arms of the loop?
1. | \(3 \overrightarrow{F}\) | 2. | \(- \overrightarrow{F}\) |
3. | \(-3 \overrightarrow{F}\) | 4. | \( \overrightarrow{F}\) |
Under the influence of a uniform magnetic field, a charged particle moves with constant speed \(v\) in a circle of radius \(R.\) The time period of rotation of the particle:
1. | depends on \(v\) and not on \(R.\) |
2. | depends on R and not on \(v.\) |
3. | is independent of both \(v\) and \(R.\) |
4. | depends on both \(v\) and \(R.\) |