Two identically charged particles A and B initially at rest, are accelerated by a common potential difference V. They enter into a transverse uniform magnetic field B. If they describe a circular path of radii respectively, then their mass ratio is:
1.
2.
3.
4.
A charge having q/m equal to 108 c/kg and with velocity 3 × 105 m/s enters into a uniform magnetic field B = 0.3 tesla at an angle 30º with the direction of field. Then the radius of curvature will be:
1. 0.01 cm
2. 0.5 cm
3. 1 cm
4. 2 cm
An electron having mass 'm' and kinetic energy E enter in a uniform magnetic field B perpendicularly. Its frequency will be:
1.
2.
3.
4.
In the Thomson mass spectrograph where the velocity of the undeflected electron beam will be:
1. \(\frac{\left| \vec{E}\right|}{\left|\vec{B} \right|}\)
2. \(\vec{E}\times \vec{B}\)
3. \(\frac{\left| \vec{B}\right|}{\left|\vec{E} \right|}\)
4. \(\frac{E^{2}}{B^{2}}\)
If a charge '\(q\)' moves with velocity \(\mathrm{v}\), in a region where electric field (\(\mathrm{E}\)) and magnetic field (\(\mathrm{B}\)) both exist, then force on it is:
1. \(q(\overrightarrow{\mathrm{v}} \times \overrightarrow{\mathrm{B}})\)
2. \(q \overrightarrow{\mathrm{E}}+\mathrm{q}(\overrightarrow{\mathrm{v}} \times \overrightarrow{\mathrm{B}})\)
3. \( q \overrightarrow{\mathrm{E}}+q(\overrightarrow{\mathrm{B}} \times \overrightarrow{\mathrm{v}})\)
4. \(\mathrm{qB}+\mathrm{q}(\overrightarrow{\mathrm{E}} \times \overrightarrow{\mathrm{v}})\)
A charged particle moves through a magnetic field in a direction perpendicular to it. Then:
1. the speed of the particle remains unchanged.
2. the direction of the particle remains unchanged.
3. the acceleration remains unchanged.
4. the velocity remains unchanged.
A very long straight wire carries a current I. At the instant when a charge +Q at point P has velocity , as shown, the force on the charge is
1. Along ox
2. Opposite to oy
3. Along oy
4. Opposite to ox