Cyclotron

Q.

Why is an electron both a particle and a wave?

Q. Three point charges are placed at the corners of an equilateral triangle Assuming only electrostatic forces are acting (a) The system can never be in equilibrium (b) The system will be in equilibrium if the charges rotate about the centre of the triangle (c) The system will be in equlibrium if the charges have different magnitudes and different signs (d) The system will be in equilibrium if the charges have the same magnitude but different signs

Q.

What does Lambda mean in physics?

Q.

What are the limitations of cyclotron

Q.

What is one important function of an electron gun?

Q.

Gravity Affects Light, But Why?

Q. What is a cyclotron?

Q. If a bar magnet of pole strength $m$ and magnetic moment $M$ is cut into $5$ equal parts parallel to its axis and $4$ parts equally perpendicular to its axis, then the pole strength and magnetic moment of each piece are respectively

1. $\frac{m}{4};\frac{M}{20}$
2. $\frac{m}{20};\frac{M}{20}$
3. $\frac{m}{5};\frac{M}{4}$
4. $\frac{m}{5};\frac{M}{20}$

Q. (a) Deduce an expression for the frequency of revolution of a charged particle in a magnetic field and show that it is independent of velocity or energy of the particle.

(b) Draw a shematic sketch of a cyclotron. Explain, giving the essential details of its construction, how it is used to accelerate the charged particles.

Q.

What are the different types of cyclotrons?

Q. A body of mass 10 gm and having charge 2C is attached to a spring which is suspended from ceiling. If it is vibrating then its time period is 1 sec. If an electric field of intensity 100 N/C is applied in the downward direction then the time period becomes:

1. 1 sec
2. 3 sec
3. 4 sec
4. $\frac{1}{2}$

Q.

$1ns$ is defined as

1. ${10}^{-9}s$ of Kr–clock of $1650763.73$ oscillations

2. ${10}^{-9}s$ of Kr–clock of$6521389.63$ oscillations

3. ${10}^{-9}s$ of Cs–clock of $1650763.73$oscillations

4. ${10}^{-9}s$ of Cs–clock of $9192631770$ oscillations

Q. A uniform but time-varying magnetic field $B\left(t\right)$ exists in a circular region of radius $a$ and is directed into the plane of the paper, as shown in the figure. The magnitude of the induced electric field at a point $P$ at a distance $r$ from the center of the circular region -

1. is zero
2. decreases as $1/r$
3. increases as $r$
4. decreases as $1/r^2$

Q.

A charged particle of mass m and charge q travels on a circular path of radius r that is perpendicular to the magnetic field B. The time taken by the particle to complete one revolution is:

1. $\frac{2{\mathrm{\pi q}}^2\mathrm{B}}{\mathrm{m}}$

2. $\frac{2\mathrm{\pi mq}}{\mathrm{B}}$

3. $\frac{2\mathrm{\pi m}}{\mathrm{qB}}$

4. $\frac{2\mathrm{\pi qB}}{\mathrm{m}}$

Q. An electron is moving in a circular path under the influence of a transverse magnetic field of $3\cdot 57\times {10}^{-2}T$. If the value of e/m is $1\cdot 76\times {10}^{11}$ C/kgg. the frequency of revolution of the electron is.

1. $6\cdot 28$ MHz
2. 1 GHZ
3. 100 MHz
4. $62\cdot 8$ MHz

Q. 32. Force between the plates of an isolated charged parallel placed capacitor separated by distance r is F. What will be the new force when distance between the plates is doubled ?

Q. A cyclotron designed to speed up protons which has a magnetic field of 0.8 Tesla over a region of radius 1.6 m, then maximum speed of protons $(q=1.6\times {10}^{-19}C,m=1.6\times {10}^{-27}kg)$

1. $128\times {10}^{6}m/s$
2. $128\times {10}^{3}m/s$
3. $32\times {10}^{6}m/s$
4. $32\times {10}^{3}m/s$

Q.

Cyclotron derivation frequency angular frequency limitations

Q. In cyclotron we apply electric field($\overrightarrow{E}$) & magnetic field($\overrightarrow{B}$) to accelerate the charged particles or ions, where $\overrightarrow{E}$ & $\overrightarrow{B}$

1. are parallel
2. are applied at some angle other than ${90}^{\circ }$
3. none of the above
4. are applied in perpendicular directions

Q.

(a) Draw a schematic sketch of a cyclotron. Explain clearly the role of crossed electric and magnetic field in accelerating the charge. Hence derive the expression for the kinetic energy acquired by the particles.
(b) An $\alpha$-particle and a photon are released from the centre of the cyclotron and made to accelerate.
(i) Can both be accelerated at the same cyclotron frequency ? Give reason to justify your answer.
(ii) When they are accelerated in turn, which of the two will have higher velocity at the exit slit of the dees ?

Q. A current carrying circular loop of radius r is placed in the x-y plane with center at the origin. Half of the loop with x > 0 is now bent so that it now lies in y - z plane. Magnitude of change in magnetic dipole momentum is [$I$ is current in loop]

1. $I\pi r^2\frac{(\sqrt{2}-1)}{/sqrt2}$
2. $\frac{I\pi r^2}{2}$
3. $\frac{I\pi r^2}{\sqrt{2}}$
4. $\frac{I\pi r^2\sqrt{2}}{(\sqrt{2}-1)}$

Q. A positively charged thin metal ring of radius R is fixed in the xy - plane with its centre at the O. A negatively charged particle P is released from rest at the point (0, 0, $z_0$), where $z_0>0$. Then the motion of P is

1. Periodic for all values of $z_0$ satisfying $0<z_0<\infty$
2. Simple harmonic for all values of satisfying $0<z_0<R$
3. Approximately simple harmonic provided $z_0<<R$
4. Such that P crosses O and continues to move along the negative z - axis towards $z=-\infty$

Q. 13.A charged particle having charge q is moving with a speed v along x axis .It enters a region of space where an electric field E=Ej and a magnetic field B are both present . The particle on emerging from this region is observed to be moving along the x axis only . What is the direction of B

Q. 54.two metal spheres each of radius r and separated by a distance d have equal and opposite charges if d is very greater than r the capacitance of the system is

Q. ntA circular disc of radius r carries a charge q , which is uniformly distributed .If the disc rotates with angular velocity omega , in its own axis then find the magnetic moment of the disc.n

Q. Assertion :Cyclotron is a device which is used to accelerate the positive ions. Reason: Cyclotron frequency depends upon the velocity.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect but Reason is correct

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 describe circular path of radius $r_1$ and $r_2$ respectively. The ratio of mass of X to that of Y is ___________.

1. $\sqrt{\left(r_1/r_2\right)}$

2. $\left(r_2/r_1\right)$

3. ${\left(r_1/r_2\right)}^2$

4. $r_1/{r_2}^2$

Q. A cyclotron is used to accelerate

1. Neutron
2. Both positively and negatively charged particles
3. Only positively charged particles
4. Only negatively charged particles

Q. A certain material has magnetic susceptibility of $+0.007$. Then the material is -

1. weakly repelled by magnetic field
2. strongly repelled by magnetic field
3. weakly attracted by magnetic field
4. strongly attracted by magnetic field

Q. What are the limitations of a cyclotron?