Braking Radiation

Q. A proton is accelerated from rest through a potential of 500v . its final kinetic energy i

Q. A proton is accelerated through a potential of 1V then its energy will be ?

Q.

The wavelength of light from the spectral emission line of sodium is 589 nm. Find the kinetic energy at which

(a) an electron, and

(b) a neutron, would have the same de Broglie wavelength.

Q.

An electron initially at rest is accelerated through a potential difference of 1 V. The energy gained by the electron is:

1. 1 J

2. 1.6 × 10^-19 J

3. None of these

4. 10^-19J

Q. Transformers increase or decrease the voltage then how is it that the law of conservation of energy not violated

Q. An X-ray tube is operating at 50 kV and 20 mA. The target material of the tube has a mass of 1.0 kg and specific heat $495Jk{g}^{-1\circ }{C}^{-1}$. One percent of the supplied electric power is converted into X-rays and the entire remaining energy goes into heating the target. Then

1. A suitable target material must have a high melting temperature
2. A suitable target material must have low thermal conductivity
3. The average rate of rise of temperature of target would be $2^{\circ }C/s$
4. The minimum wavelength of the X-rays emitted is about $0.25\times {10}^{-10}m$

Q. 106. 3 capacitor are connected as shown in the figure. The potential at point O is A)1.4volt B)4.7volt C)0 D)1.8volt

Q. When a cathode ray tube is operated at 2912 V, the velocity of electrons is $3.2\times {10}^{7}m{s}^{-1}$, find the velocity of cathode ray, if tube is operated at 5824 V

1. $2.4\times {10}^{7}m{s}^{-1}$
2. $4.5\times {10}^{7}m{s}^{-1}$
3. $2.4\times {10}^{5}m{s}^{-1}$
4. $2.4\times {10}^{8}m{s}^{-1}$

Q. Suppose an attractive nuclear force acts between two protons which may be written as F=Ce^−kr/r². (a) Write down the dimensional formulae and appropriate SI units of C and k. (b) Suppose that k = 1 fermi⁻¹ and that the repulsive electric force between the protons is just balanced by the attractive nuclear force when the separation is 5 fermi. Find the value of C.

Q. In a photon-particle collision (like photon-electron), the photons -

1. may be created.
2. may be absorbed.
3. always remain conserved.
4. Both options $\left(A\right)$ and $\left(B\right)$

Q. An electron passing near a positively charged nucleus should get accelerated due to the attractive force, and it's speed should increase. But the opposite is observed! It's found to get slowed down. Why do you think?

1. The electron loses a lot of energy in radiation when its accelerated by the nucleus, resulting in a decrease in kinetic energy
2. The electron's kinetic energy is converted into electrostatic potential energy
3. Law of conservation of energy doesn't apply to sub-atomic particles.

Q. If the current in the circuit for heating the filament is increased, the cut-off wavelength

1. Will change
2. Will increase
3. Will decrease
4. Will remain unchanged

Q.

An electric dipole if moment p is placed normal to the lines of force of electric intensity E , then the work done in rotating it through an angle of 180, is? In this question, which initial angle should be taken ? I am facing problem in application type question , where I am in dilemma to take which as initial angle

Q. At t = 0, light of intensity $\frac{{10}^{12}photons}{s{m}^2}$ of energy 6eV per photon start falling on a plate with work function 2.5 eV. If area of the plate is $2\times {10}^{-4}{m}^2$ and for every ${10}^5$ photons one photoelectron is emitted, charge on the plate at t = 25 s is

1. $8\times {10}^{-14}C$
2. $4\times {10}^{-14}C$
3. $12\times {10}^{-14}C$
4. $16\times {10}^{-14}C$

Q. Assertion :If the accelerating potential in an X-ray tube is increased, the wavelengths of the characteristic X-rays do not decrease. Reason: When an electron beam strikes the target in an X-ray tube, part of the kinetic energy is converted into X-ray energy.

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.

The wavelength of a probe is roughly a measure of the size of a structure that it can probe in some detail. The quark structure of protons and neutrons appears at the minute length-scale of 10⁻¹⁵ m or less. This structure was first probed in early 1970’s using high energy electron beams produced by a linear accelerator at Stanford, USA. Guess what might have been the order of energy of these electron beams. (Rest mass energy of electron = 0.511 MeV.)

Q.

When a fast electron passes near a highly positively charged nucleus, x-rays are seen to get radiated. What could be the cause for this radiation?

1. All interactions between two charged particles result in radiation of energy
2. The nucleus deflects the electron inwards, giving it a centripetal acceleration, which causes the radiation from the charged electron
3. The nucleus speeds the electron up, giving rise to radiation from an accelerated charge
4. The radiation comes from the nucleus because of the change in its energy due to the electron.

Q.

In an accelerator experiment on high-energy collisions of electrons with positrons, a certain event is interpreted as annihilation of an electron-positron pair of total energy 10.2 BeV into two γ-rays of equal energy. What is the wavelength associated with each γ-ray? (1BeV = 10⁹ eV)

Q. 24 When a proton is accelerated through 1V then its kinetic energy will be

Q. The potential difference applied to an x-ray tube is 5 KV and the current through it is 32 mA. The number of electrons striking the target per second is $(e=1.6\times {10}^{-19}C)$

1. $2\times {10}^{-6}{s}^{-1}$
2. $1.6\times {10}^6{s}^{-1}$
3. $4\times {10}^{16}{s}^{-1}$
4. $2\times {10}^{16}{s}^{-1}$

Q. An electron with initial kinetic energy of $100$eV is acceleration through a potential difference of $50$V. Now the de-Broglie wavelength of electron becomes.

1. $1\stackrel{o}{A}$
2. $\sqrt{1.5}\stackrel{o}{A}$
3. $\sqrt{3}\stackrel{o}{A}$
4. $12.27\stackrel{o}{A}$

Q. An electron of mass $m$ and charge $e$ is accelerated from rest through a potential difference of $V$ volt in vacuum. Its final speed will be

1. $\frac{eV}{2m}$
2. $\frac{eV}{m}$
3. $\sqrt{\frac{2eV}{m}}$
4. $\sqrt{\frac{eV}{2m}}$

Q. If a Coolidge tube operators at 20kV, what is the maximum kinetic energy you'll find among the electrons near the target?

1. 20eV
2. 200eV
3. 2, 000 eV
4. 20, 000eV

Q. An inductor is connected to a battery through a switch. Explain why the emf induced in the inductor is much larger when the switch is opened as compared to the emf induced when the switch is closed.

Q. A particle A of mass 'm' and charge 'q' is accelerated by a potential difference of $50V$. Another particle B of mass '4 m' and charge 'q' is accelerated by a potential difference of $2500V$ The ratio of de-Broglie wavelengths $\frac{{\lambda }_A}{{\lambda }_B}$ is close to :

1. $10.00$
2. $14.14$
3. $4.47$
4. $0.07$

Q. An Alpha particle is accelerated from rest through a potential of V volts its final kinetic energy

Q.

The de-Broglie wavelength of an electron, accelerated by potential V is $\lambda$. What will be the de-Broglie wavelength of the electron which is accelerated by 4V potential?

Q. An electron and a proton are detected in a cosmic ray experiment, the first with kinetic energy $10keV$, and the second with $100keV$. The ratio of their speeds is
(where $m_e$ and $m_p$ are masses of electrons and proton respectively).

1. $\sqrt{\frac{1}{10}\frac{m_e}{m_p}}$
2. $\sqrt{\frac{1}{10}\frac{m_p}{m_e}}$
3. $\frac{1}{10}\frac{m_p}{m_e}$
4. $\frac{1}{10}\frac{m_e}{m_p}$

Q.

In photo-electric effect, the photo-electric current

1. Increases when the frequency of incident photon increases
2. Does not depend upon the photon frequency but depends on the intensity of incident beam
3. Depends both on the intensity and frequency of the incident beam.
4. Decreases when the frequency of incident photon decreases

Q. Consider a photon of a continuous X-ray coming from a Coolidge tube. Its energy comes from
(a) the kinetic energy of the striking electron
(b) the kinetic energy of the free electrons of the target
(c) the kinetic energy of the ions of the target
(d) an atomic transition in the target