**Question No:1 **

A ray of light of wavelength 5030A^{0} is incident on a totally reflecting surface. The momentum delivered by the ray is equal to

**[A]** 6.63 x10^{-27 }kg-m/s

**[B]** 2.63 x10^{-27} kg-m/s

**[C]** 1.25 x10^{-24 }kg-m/s

**[D]** None of the above

**Question No:2 **

What is the binding energy per nucleon of_{ 6}C^{12} nucleus?

Given : Mass of C^{12} (m_{c}) = 12.000u

Mass of proton (m_{p}) = 1.0078u

Mass of neutron (m_{n}) = 1.0087 u

And 1 amu= 931.4 \( \frac{MeV}{C^2}\)

**[A]** 5.26 MeV

**[B]** 6.2 MeV

**[C]** 4.65 MeV

**[D]** 7.68 MeV

**Question No:3 **

Energy of 24.6 eV is required to remove one of the electrons from a neutral helium atom. The energy (in eV) required to remove both the electrons from a neutral helium atom is

**[A]** 38.2

**[B]** 49.2

**[C]** 51.8

**[D]** 79.0

**Question No:4**

If the radius of first Bohr’s orbit is “x”, then de-Broglie wavelength of electron in 3rd orbit is nearly

**[A]** 2πx

**[B]** 6πx

**[C]** 9x

**[D]** \(\frac{X}{3}\)

**Question No:5 **

A star initially has 10^{40}deuterons. It produces energy via the processes_{1}^{2}H +_{1}^{2}H—–>_{1}^{2}H +p and _{1}^{2}H+ _{1}^{3}H—–>_{2}^{4} He+n Where the masses of the nuclei are m(^{2}H) =2.014amu, m(p) = 1.007 amu, m(n) = 1.008 amu and m((^{4(}He) =4.001 amu, if the average power radiated by the star is 10(^{16}W. The deuteron supply of the star is exhausted in a time of the order of

**[A]** 10^{18}s

**[C]** 10^{12} s

**[B]** 10^{28}s

**[D]** 10^{16}s

**Question No:6 **

Assuming that about 200 MeV energy is released per fission of _{92} U^{235} nuclei. What would be the mass of U^{235} consumed per day in the fission of reactor of power 1 MW approximately?

**[A]** 10kg

**[B]** 1kg

**[C]** 1 g

**[D]** 10 g

**Question No:7 **

The ratio between acceleration of the electron in singly ionized helium atom and doubly ionized lithium atom (both in ground state) is

**[A]** \( \frac{4}{9}\)

**[B]** \( \frac{27}{8}\)

**[C]**c) \( \frac{8}{27}\)

**[D]**d) \( \frac{9}{4}\)

**Question No:8 **

A H-atom moving with speed v makes a head on collision with a H-atom at rest. Both atoms are in ground state. The minimum value of velocity v for which one of the atom may excite is

**[A]** 6.25 x 10^{4} m/s

**[B]** 8 x 10^{4 }m/s

**[C]** 7.25 x 10^{4} m/s

**[D]** 13.6 x 10^{4} m/s

Note : m_{H} = 1.67 x 10^{-27 } kg

**Question No:9 **

In the reaction_{1}^{2}H+ _{2}^{3}H——>_{2}^{4}He+_{0}^{1}n, if the binding energies per nucleon of _{1}^{2}H, _{1}^{3} H and_{2}^{4}He, are x, y and z respectively. Then energy released in the process is

**[A]** 2x + 3y – 4z

**[B]** 4z – 2x – 3y

**[C]** Zx + 3y – 5z

**[D]** None of these

**Question No:10 **

In Moseley’s equation,\( \sqrt{ v} = a( Z — b)\) , for X-rays

**[A]** a is independent but b depends on target material

**[B]** both a and b are independent of the target material

**[C]** both a and b depend on the target material

**[D]** b is independent but a depends on the target material

**Question No:11 **

. The activity of a sample of radioactive material is A_{1} at time t_{1} and A_{2} at time t_{2} (t_{2} > t_{1}). Its mean life is T. Then

**[A]** A_{1}t_{1} = A_{2}t_{2}

**[B]**\( \frac{A_1-A_2}{t_2-t_1}\) = constant

**[C]** A_{2}=A_{1}e^{\( \frac{(t_1-t_2)}{T} \)}

None of these

**Question No:12**

A particular nucleus in a large population of identical radioactive nuclei did survive 5 half lifes of that isotope. Then the probability that this surviving nucleus will survive the next half-life is

**[A]**\( \frac{1}{32}\)

**[B]** \(\frac{1}{5}\)

**[C]** \( \frac{1}{2}\)

**[D]** \( \frac{1}{10}\)

**Question No:13 **

Two electrons are moving with the same speed v. One electron enters a region of uniform electric field while the other enters a region of uniform magnetic field. Then after some time if the de-Broglie wavelengths of the two are λ_{1} and λ_{1} then

**[A]** λ_{1} =λ_{2}

**[B]** λ_{1} > λ_{1}

**[C]** λ_{1} < λ_{2}

**[D]** λ_{1}>λ_{2} or λ_{1} <λ_{2}

**Question No:14 **

A stationary radioactive nucleus of mass 210 units disintegrates into an alpha particle of mass 4 units and residual nucleus of mass 206 units. If the kinetic energy of the alpha particle is E, the kinetic energy of the residual nucleus is

**[A]** \(\frac{2}{105}\)

**[B]**\(\frac{2}{103}\)

**[C]**\(\frac{103}{2}\)

**[D]**\(\frac{105}{2}\)

**Question No:15 **

The magnetic field at the centre of a hydrogen atom due to the motion of the electron in the first Bohr orbit is **B**. The magnetic field at the centre due to the motion of the electron in the second Bohr orbit will be

**[A]** \( \frac{B}{4}\)

**[B]** \(\frac{B}{8}\)

**[C]** \(\frac{B}{32}\)

**[D]** \(\frac{B}{64}\)

**Question No:16 **

An excited hydrogen atom emits a photon of wavelength K in returning to the ground state. The quantum number n of the excited state is given by (R = Rydberg constant)

**[A]** \( \sqrt{λR(λR-1) }\)

**[B]** \( \sqrt\frac{λR}{(λR-1) }\)

**[C]** \( \sqrt\frac{(λR-1) }{λR}\)

**[D]** \( \sqrt\frac{1}{λR(λR-1) }\)

**Question No:17 **

17. Magnetic moment of an electron in nth orbit of hydrogen atom is

**[A]**\(\frac{neh}{πm}\)

**[B]**\(\frac{neh}{4πm}\)

**[C]** \(\frac{meh}{4πn}\)

**[D]**\(\frac{meh}{4πn}\)

[m = mass of electron, h = Planck’s constant]

**Question No:18 **

The probability of survival of a radioactive nucleus for one mean life is

**[A]**\( \frac{1}{e}\)

**[B]**\( (1-\frac{1}{e}) \)

**[C]**\(\frac{ln2}{e}\)

**[D]**\( 1- \frac{ln2}{e} )\)

**Question No:19 **

When the voltage applied to an X-ray tube is increased from V_{1} = 1 0 kV to V_{2} =20 kV, the wavelength difference between the K_{α} line and the short wavelength limit of the continuous X-ray spectrum increases by a factor 3. The atomic number of the element of which the tube anticathode is made will be

**[A]** 62

**[B]** 56

**[C]** 45

**[D]** 29

**Question No:20 **

Light of wavelength 330 nm falling on a piece of metal ejects electrons with sufficient energy with requires voltage V_{0} to prevent them from reaching a collector. In the same setup, light of wavelength 220 nm, ejects electrons which require twice the voltage V_{0} to stop them in reaching a collector. The numerical value of voltage V_{0} is

**[A]** \(\frac{16}{15}\)V

**[B]** \(\frac{15}{16}\)V

**[C]** \(\frac{15}{8}\)V

**[D]** \(\frac{8}{15}\)V

**Question No:21 **

Maximum KE of a photoelectron is E when the wavelength of incident light is λ If energy becomes four times when wavelength is reduced to one-third, then work function of the metal is

**[A]**\(\frac{3hc}{λ}\)

**[B]**\(\frac{hc}{3λ}\)

**[C]**\(\frac{hc}{λ}\)

**[D]**\(\frac{hc}{2λ}\)

**Question No:22 **

If the frequency of **K _{α}** X-ray emitted from the element with atomic number 31 is “

**f**”, then the frequency of

**K**X-ray emitted from the element with atomic number 51 would be

_{α}**[A]**\(\frac{5f}{3}\)

**[B]**\(\frac{51f}{31}\)

**[C]**\(\frac{9f}{25}\)

**[D]**\(\frac{25f}{9}\)