Circular Kinematics

Q. When a charged particle circulates in a normal magnetic field, then the area of its circulation is proportional to

1. its charge
2. its momentum
3. its kinetic energy
4. Magnetic fields intensity

Q. A particle of mass m and charge q moves with a constant velocity v along the positive x direction. It enters a region containing a uniform magnetic field B directed along the negative z direction extending from x = a to x = b. The minimum value of v required so that the particle can just enter the region x > b is

1. qbB/m
2. q(b – a)B/m
3. qaB/m
4. q(b+a)B/2m

Q. Electrons move at right angle to a magnetic field of $1.5\times {10}^{-2}$ Tesla with a speed of $6\times {10}^7$ m/s. If the specific charge of the electron is $1.7\times {10}^{11}$ C/kg, then the radius of the circular path will be?

1. 2.9 cm
2. 3.9 cm
3. 3 cm
4. 2.35 cm

Q. An $\alpha$ particle and a proton travel with same velocity in a magnetic field perpendicular to the direction of their velocities, find the ratio of the radii of their circular path

1. 4 : 1
2. 1 : 4
3. 2 : 1
4. 1 : 2

Q. A proton and an $\alpha$- particle enter a uniform magnetic field perpendicularly with the same speed. If proton takes $25\mu sec$ to make 5 revolutions, then the periodic time for the $\alpha$ - particle would be

1. $25\mu sec$.
2. $50\mu sec$.
3. $10\mu sec$.
4. $5\mu sec$.

Q. $H^{+},H{e}^{+}$ and $O^{++}$ ions having same kinetic energy pass through a region of space filled with uniform magnetic field B directed perpendicular to the velocity of ions. The masses of the ions $H^{+},H{e}^{+}$ and $O^{++}are$ respectively in the ratio 1:4:16 . Choose the correct statement.

1. $O^{++}$ ions will be deflected least
2. $H^{+}$ and $O^{++}$ ions will suffer different deflections
3. All ions will suffer the same deflection
4. $H^{+}$ ions will be deflected most

Q. A charge moves in a circle perpendicular to a magnetic field. The time period of revolution is independent of

1. Velocity of the particle
2. Mass of the particle
3. Magnetic field
4. Charge

Q. An electron and a proton with equal momentum enter perpendicularly into a uniform magnetic field, then

1. The path of proton shall be less curved than that of electron
2. Path of both will be straight line
3. The path of proton shall be more curved than that of electron
4. Both are equally curved

Q. Two particles X and Y having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describes circular path of radius $R_1$ and $R_2$ respectively. The ratio of mass of X to that of Y is

1. 
2. 
3. 
4. 

Q.

The radius of curvature of the path of the charged particle in a uniform magnetic field is directly proportional to

[MNR 1995; UPSEAT 1999, 2000]

1. The intensity of the field

2. The charge on the particle

3. The momentum of the particle

4. The energy of the particle