A charged particle moves along a circle under the action of possible constant electric and magnetic fields. Which of the following are possible?
(a) | \(E=0, ~B=0\) |
(b) | \(E=0, ~B\ne0\) |
(c) | \(E\ne0, ~B=0\) |
(d) | \(E\ne0, ~B\ne0\) |
Choose the correct option:
1. (a), (b)
2. (b) only
3. (c), (d)
4. (a), (d)
A charged particle goes undeflected in a region containing electric and magnetic field. It is possible that
(a) \(\overrightarrow{\mathrm{E}}\|\overrightarrow{\mathrm{B}} \quad \overrightarrow{\mathrm{v}}\| \overrightarrow{\mathrm{E}}\)
(b) \(\overrightarrow{\mathrm{E}}\) is not parallel to \(\overrightarrow{\mathrm{B}}\)
(c) \(\overrightarrow{\mathrm{v}} \| \overrightarrow{\mathrm{B}}\) but \(\overrightarrow{\mathrm{E}}\) is not parallel to \(\overrightarrow{\mathrm{B}}\)
(d) \(\overrightarrow{\mathrm{E}} \| \overrightarrow{\mathrm{B}}\) but \(\overrightarrow{\mathrm{v}}\) is not parallel to \(\overrightarrow{\mathrm{E}}\)
Choose the correct option
1. (a), (b)
2. (b), (c)
3. (c), (d)
4. (a), (d)
If a charged particle goes unaccelerated in a region containing electric and magnetic fields,
(a) \(\overrightarrow{\mathrm{E}}\) must be perpendicular to \(\overrightarrow{\mathrm{B}}\)
(b) \(\overrightarrow{\mathrm{v}}\) must be perpendicular to \(\overrightarrow{\mathrm{E}}\)
(c) \(\overrightarrow{\mathrm{v}}\) must be perpendicular to \(\overrightarrow{\mathrm{B}}\)
(d) E must be equal to vB.
Choose the correct option
1. (a), (b)
2. (b), (c)
3. (c), (d)
4. (a), (d)
Two ions have equal masses but one is singly-ionized and the other is doubly-ionized. They are projected from the same place in a uniform magnetic field with the same velocity perpendicular to the field.
(a) Both ions will go along circles of equal radii.
(b) The circle described by the singly-ionized charge will have a radius double that of the other circle.
(c) The two circles do not touch each other.
(d) The two circles touch each other.
Choose the correct option:
1. (a), (b)
2. (b), (c)
3. (b), (d)
4. (a), (d)
An electron is moving along the positive x-axis. You want to apply a magnetic field for a short time so that the electron may reverse its direction and move parallel to the negative x-axis. This can be done by applying the magnetic field along
(a) y-axis
(b) z-axis
(c) y-axis only
(d) z-axis only
Choose the correct option:
1. (a), (b)
2. (b), (c)
3. (c), (d)
4. (a), (d)
Let \(\overrightarrow{\mathrm{E}}\)and \(\overrightarrow{\mathrm{B}}\)denote electric and magnetic fields in a frame S and \(\overrightarrow{\mathrm{E}}\) and \(\overrightarrow{\mathrm{B}}\) in another frame S' moving with respect to S at a velocity \(\overrightarrow{\mathrm{v}}\) Two of the following are wrong. Identify them.
(a) By’ = By + \(\frac{\mathrm{vE}_{\mathrm{z}}}{\mathrm{c}^{2}}\)
(b) Ey’ = Ey – \(\frac{\mathrm{vB}_{\mathrm{z}}}{\mathrm{c}^{2}}\)
(c) B’y = By + vEz
(d) E’y = Ey + vBz
Choose the correct option
1. (a), (b)
2. (b), (c)
3. (c), (d)
4. (a), (d)
A vertical wire carries a current in an upward direction. An electron beam sent horizontally towards the wire will be deflected
1. towards right
2. towards left
3. upwards
4. downwards
A current-carrying straight wire is kept along the axis of a circular loop carrying a current. The straight wire
1. | will exert an inward force on the circular loop |
2. | will exert an outward force on the circular loop |
3. | will not exert any force on the circular loop |
4. | will exert a force on the circular loop parallel to itself |
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 |
A circular loop is kept in that vertical plane which contains the north-south direction. It carries a current that is towards north at the topmost point. Let A be a point on the axis of the circle to the east of it and B a point on this axis to the west of it. The magnetic field due to the loop
1. is towards east at A and towards west at B
2. is towards west at A and towards east at B
3. is towards east at both A and B
4. is towards west at both A and B