Q16. For the thin convex lens, the radii of curvature are at 15 cm and 30 cm respectively. The focal length the lens is 20 cm . The refractive index of the material is :
(1) 1.2
(2) 1.8
(3) 1.5
(4) 1.4

Q16. A proton and an electron are associated with same de-Broglie wavelength. The ratio of their kinetic energies is: (Assume $\mathrm { h } = 6.63 \times 10 ^ { - 34 } \mathrm {~J} \mathrm {~s} , \mathrm {~m} _ { \mathrm { e } } = 9.0 \times 10 ^ { - 31 } \mathrm {~kg}$ and $\mathrm { m } _ { \mathrm { p } } = 1836$ times $\mathrm { m } _ { \mathrm { e } }$ )
(1) $1 : \sqrt { 1836 }$
(2) $1 : \frac { 1 } { 1836 }$
(3) $1 : \frac { 1 } { \sqrt { 1836 } }$
(4) $1 : 1836$

Q16. A proton and an electron have the same de Broglie wavelength. If $K _ { p }$ and $K _ { e }$ be the kinetic energies of proton and electron respectively, then choose the correct relation :
(1) $K _ { p } > K _ { e }$
(2) $\mathrm { K } _ { \mathrm { p } } < \mathrm { K } _ { \mathrm { e } }$
(3) $K _ { p } = K _ { e }$
(4) $\mathrm { K } _ { \mathrm { p } } = \mathrm { K } _ { \mathrm { e } } { } ^ { 2 }$

Q16. Given below are two statements : Statement (I) : When an object is placed at the centre of curvature of a concave lens, image is formed at the centre of curvature of the lens on the other side. Statement (II) : Concave lens always forms a virtual and erect image. In the light of the above statements, choose the correct answer from the options given below :
(1) Both Statement I and Statement II are true
(2) Both Statement I and Statement II are false
(3) Statement I is true but Statement II is false
(4) Statement I is false but Statement II is true

Q16. A hydrogen atom in ground state is given an energy of 10.2 eV . How many spectral lines will be emitted due to transition of electrons?
(1) 6
(2) 3
(3) 10
(4) 1

Q17. An effective power of a combination of 5 identical convex lenses which are kept in contact along the principal axis is 25 D . Focal length of each of the convex lens is :
(1) 20 cm
(2) 50 cm
(3) 500 cm
(4) 25 cm

Q17. Given below are two statements: one is labelled as Assertion $\mathbf { A }$ and the other is labelled as Reason $R$. Assertion A: Number of photons increases with increase in frequency of light. Reason R: Maximum kinetic energy of emitted electrons increases with the frequency of incident radiation. In the light of the above statements, choose the most appropriate answer from the options given below:
(1) Both $\mathbf { A }$ and $\mathbf { R }$ are correct and $\mathbf { R }$ is the correct explanation of $\mathbf { A }$.
(2) Both $\mathbf { A }$ and $\mathbf { R }$ are correct and $\mathbf { R }$ is NOT the correct explanation of $\mathbf { A }$.
(3) $\mathbf { A }$ is not correct but $\mathbf { R }$ is correct.
(4) $\mathbf { A }$ is correct but $\mathbf { R }$ is not correct.

Q17. Light emerges out of a convex lens when a source of light kept at its focus. The shape of wavefront of the light is :
(1) both spherical and cylindrical
(2) plane
(3) spherical
(4) cylindrical

Q17. Which of the following statement is not true about stopping potential $\left( \mathrm { V } _ { 0 } \right)$ ?
(1) It is $1 /$ e times the maximum kinetic energy of
(2) It increases with increase in intensity of the electrons emitted. incident light. $( 3 )$ It depends on the nature of emitter material.
(4) It depends upon frequency of the incident light.

Q17. Which of the following phenomena does not explain by wave nature of light. A. reflection B. diffraction C. photoelectric effect D. interference E. polarization Choose the most appropriate answer from the options given below:
(1) E only
(2) B, D only
(3) C only
(4) A, C only

Q17. When UV light of wavelength 300 nm is incident on the metal surface having work function 2.13 eV , electron emission takes place. The stopping potential is: (Given hc $= 1240 \mathrm { eVnm }$ )
(1) 1.5 V
(2) 4.1 V
(3) 2 V
(4) 4 V

Q17. Average force exerted on a non-reflecting surface at normal incidence is $2.4 \times 10 ^ { - 4 } \mathrm {~N}$. If $360 \mathrm {~W} / \mathrm { cm } ^ { 2 }$ is the light energy flux during span of 1 hour 30 minutes, Then the area of the surface is:
(1) $0.2 \mathrm {~m} ^ { 2 }$
(2) $20 \mathrm {~m} ^ { 2 }$
(3) $0.1 \mathrm {~m} ^ { 2 }$
(4) $0.02 \mathrm {~m} ^ { 2 }$

Q17. If $M _ { o }$ is the mass of isotope ${ } _ { 5 } ^ { 12 } B , M _ { P }$ and $M _ { n }$ are the masses of proton and neutron, then nuclear binding energy of isotope is :
(1) $\left( M _ { o } - 5 M _ { p } \right) C ^ { 2 }$
(2) $\left( 5 M _ { p } + 7 M _ { n } - M _ { o } \right) C ^ { 2 }$
(3) $\left( M _ { 0 } - 12 M _ { n } \right) C ^ { 2 }$
(4) $\left( M _ { o } - 5 M _ { p } - 7 M _ { n } \right) C ^ { 2 }$

Q17. A proton, an electron and an alpha particle have the same energies. Their de-Broglie wavelengths will be compared as :
(1) $\lambda _ { \alpha } < \lambda _ { \mathrm { p } } < \lambda _ { \mathrm { e } }$
(2) $\lambda _ { \mathrm { e } } > \lambda _ { \alpha } > \lambda _ { \mathrm { p } }$
(3) $\lambda _ { \mathrm { p } } > \lambda _ { \mathrm { e } } > \lambda _ { \alpha }$
(4) $\lambda _ { \mathrm { p } } < \lambda _ { \mathrm { e } } < \lambda _ { \alpha }$

Q17. A nucleus at rest disintegrates into two smaller nuclei with their masses in the ratio of $2 : 1$. After disintegration they will move :
(1) in the same direction with same speed.
(2) in opposite directions with the same speed.
(3) in opposite directions with speed in the ratio of
(4) in opposite directions with speed in the ratio of 2 : 1 respectively. $1 : 2$ respectively.

Q18. Which figure shows the correct variation of applied potential difference (V) with photoelectric current (I) at two different intensities of light $\left( \mathrm { I } _ { 1 } < \mathrm { I } _ { 2 } \right)$ of same wavelengths :
(1) [Figure]
(2) [Figure]
(3) [Figure]
(4) [Figure]

Q18. According to Bohr's theory, the moment of momentum of an electron revolving in $4 ^ { \text {th } }$ orbit of hydrogen atom is:
(1) $\frac { h } { \pi }$
(2) $\frac { h } { 2 \pi }$
(3) $8 \frac { h } { \pi }$
(4) $2 \frac { h } { \pi }$

Q18.
Given below are two statements : [Figure] Statement I : Figure shows the variation of stopping potential with frequency $( v )$ for the two photosensitive materials $\mathrm { M } _ { 1 }$ and $\mathrm { M } _ { 2 }$. The slope gives value of $\frac { h } { e }$, where $h$ is Planck's constant, $e$ is the charge of electron. Statement II : $\mathrm { M } _ { 2 }$ will emit photoelectrons of greater kinetic energy for the incident radiation having same frequency. In the light of the above statements, choose the most appropriate answer from the options given below.
(1) Both Statement I and Statement II are correct
(2) Statement I is incorrect but Statement II is correct
(3) Both Statement I and Statement II are incorrect
(4) Statement I is correct and Statement II is incorrect

Q18. The angular momentum of an electron in a hydrogen atom is proportional to : (Where $r$ is the radius of orbit of electron)
(1) $r$
(2) $\sqrt { \mathrm { r } }$
(3) $\frac { 1 } { \sqrt { \mathrm { r } } }$
(4) $\frac { 1 } { r }$

Q18. The ratio of the shortest wavelength of Balmer series to the shortest wavelength of Lyman series for hydrogen atom is :
(1) $4 : 1$
(2) $1 : 4$
(3) $2 : 1$
(4) $1 : 2$

Q18. The longest wavelength associated with Paschen series is : (Given $R _ { H } = 1.097 \times 10 ^ { 7 } \mathrm { SI }$ unit)
(1) $3.646 \times 10 ^ { - 6 } \mathrm {~m}$
(2) $1.876 \times 10 ^ { - 6 } \mathrm {~m}$
(3) $2.973 \times 10 ^ { - 6 } \mathrm {~m}$
(4) $1.094 \times 10 ^ { - 6 } \mathrm {~m}$

Q18. Binding energy of a certain nucleus is $18 \times 10 ^ { 8 } \mathrm {~J}$. How much is the difference between total mass of all the nucleons and nuclear mass of the given nucleus:
(1) $10 \mu \mathrm {~g}$
(2) $20 \mu \mathrm {~g}$
(3) $0.2 \mu \mathrm {~g}$
(4) $2 \mu \mathrm {~g}$

Q18. In a hypothetical fission reaction ${ } _ { 92 } X ^ { 236 } \rightarrow { } _ { 56 } Y ^ { 141 } + { } _ { 36 } Z ^ { 92 } + 3 R$ The identity of emitted particles $( \mathrm { R } )$ is :
(1) Electron
(2) Neutron
(3) $\gamma$-radiations
(4) Proton

Q18. The energy equivalent of 1 g of substance is :
(1) $5.6 \times 10 ^ { 12 } \mathrm { MeV }$
(2) $5.6 \times 10 ^ { 26 } \mathrm { MeV }$
(3) $11.2 \times 10 ^ { 24 } \mathrm { MeV }$
(4) 5.6 eV

Q18. The energy released in the fusion of 2 kg of hydrogen deep in the sun is $E _ { H }$ and the energy released in the fission of 2 kg of ${ } ^ { 235 } \mathrm { U }$ is $E _ { U }$. The ratio $\frac { E _ { H } } { E _ { U } }$ is approximately: (Consider the fusion reaction as $4 \mid H + 2 \mathrm { e } ^ { - } \rightarrow { } _ { 2 } ^ { 4 } \mathrm { He } + 2 v + 6 \gamma + 26.7 \mathrm { MeV }$, energy released in the fission reaction of ${ } ^ { 235 } \mathrm { U }$ is 200 MeV per fission nucleus and $\mathrm { N } _ { \mathrm { A } } = 6.023 \times 10 ^ { 23 }$ )
(1) 7.62
(2) 25.6
(3) 15.04
(4) 9.13