DUET Question Paper 2020 for DU BEd MSc Physics

DU MSc Physics
Topic:‐ PHY MSC S2

1) An atomic transition line with wavelength 350 nm is observed to be split into three components in a spectrum of light
from a sunspot. Adjacent components are separated by 1.7 pm. Determine the strength of the magnetic field in the
sunspot
[Question ID = 6662]
1. 3 T [Option ID = 26642]
2. 0.03 T [Option ID = 26643]
3. 3.3 T [Option ID = 26644]
4. 0.3 T [Option ID = 26645]

0.3 T [Option ID = 26645]

2) which one of the following is correct in respect of an electron and a proton having a same de‐Broglie wavelength of 2 Å
[Question ID = 6663]
1. Both have same kinetic energy [Option ID = 26646]
2. Both have same velocity [Option ID = 26647]
3. Both have same momentum [Option ID = 26648]
4. The kinetic energy of proton is more than that of electron [Option ID = 26649]

Both have same momentum [Option ID = 26648]

3) If rp & rH are the radius and Ep & EH are the energy of an electron in the nth orbit of positronium atom and hydrogen
atom respectively, then

[Question ID = 6664]
1. rp = 2 rH and Ep = EH /2

[Option ID = 26650]
2. rp = 2 rH and Ep = 2 EH

[Option ID = 26651]
3. rp = 2 rH and Ep = EH /4

[Option ID = 26652]
4. rp = rH and Ep = 2 EH

[Option ID = 26653]

rp = 2 rH and Ep = EH /2

[Option ID = 26650]

4) An X‐ray beam of wavelength 0.16 nm is incident on a set of planes of a certain crystal. The first Bragg reflection is
observed for an incidence angle of 30°. What is the corresponding inter planar spacing?
[Question ID = 6669]
1. 0.16 nm [Option ID = 26670]
2. 0.67 nm [Option ID = 26671]
3. 1.02 nm [Option ID = 26672]
4. 0.89 nm [Option ID = 26673]

0.16 nm [Option ID = 26670]

5) What is the velocity of conduction electron of silver having Fermi energy 5.52 eV
[Question ID = 6670]
1. 1.39 × 106 m/s [Option ID = 26674]
2. 2.39 x 106 m/s [Option ID = 26675]
3. ​0.89 × 106 m/s [Option ID = 26676]
4. 0 [Option ID = 26677]

1.39 × 106 m/s [Option ID = 26674]

6) Given that a piece of n‐type silicon contains 8 × 1021 m−3 phosphorus impurity atoms, calculate the carrier concentration
of silicon at room temperature. Given that the intrinsic electron concentration of silicon at room temperature is 1.6 × 1016
m−3

[Question ID = 6671]
1. 3.2 x 1010 m‐3 [Option ID = 26678]
2. 2.3 x 1011 m‐3 [Option ID = 26679]
3. 1.5 x 1010 m‐3 [Option ID = 26680]
4. 3.2 x 1011 m‐3 [Option ID = 26681]

3.2 x 1010 m‐3 [Option ID = 26678]

7) The dispersion relation for a one‐dimensional monoatomic lattice chain is given by the equation, ω ,
where, ‘a’ is the interatomic spacing, and has the dimension of velocity. The relation between the phase
velocity VP​ and group velocity V​g ​ in the long wavelength limit is given by

[Question ID = 6674]
1. VP​​ = V​g

[Option ID = 26690]
2. VP​​ = 2V​g

[Option ID = 26691]
3. VP​​ = V​g/2

[Option ID = 26692]
4. Vp ≠ Vg

[Option ID = 26693]

VP​​ = V​g

[Option ID = 26690]

8) The largest wavelength of light falling on double slits separated by 1.5 μm, for which there is a first order maximum is in
the,
[Question ID = 6676]
1. ultraviolet range [Option ID = 26698]
2. visible range [Option ID = 26699]
3. infrared range [Option ID = 26700]
4. X‐ray range [Option ID = 26701]

infrared range [Option ID = 26700]

9) In a multi‐stage R‐C coupled amplifier, the coupling capacitor
[Question ID = 6680]
1. limits the low frequency response [Option ID = 26714]
2. limits the high frequency response [Option ID = 26715]
3. reduces the amplitude of input signal [Option ID = 26716]
4. blocks d.c. component without affecting the frequency response [Option ID = 26717]

blocks d.c. component without affecting the frequency response [Option ID = 26717]

10) An AM transmitter is coupled to an aerial. The input current is found to be 5 A. With modulation the current value
increases to 5.9 A. The depth of modulation is
[Question ID = 6681]
1. 83.4% [Option ID = 26718]
2. 88.6% [Option ID = 26719]
3. 78.2% [Option ID = 26720]
4. 74.3% [Option ID = 26721]

88.6% [Option ID = 26719]

11) Hexadecimal equivalent of a digital number 10011101 is
[Question ID = 6683]
1. H913 [Option ID = 26726]
2. 9D [Option ID = 26727]
3. AE [Option ID = 26728]
4. 157 [Option ID = 26729]

9D [Option ID = 26727]

12) If the doping concentration in a Si‐Zener diode is increased, the Zener breakdown voltage
[Question ID = 6684]

1. Decreases [Option ID = 26730]
2. Increases [Option ID = 26731]
3. Remains unchanged [Option ID = 26732]
4. Becomes broader [Option ID = 26733]

Decreases [Option ID = 26730]

13) Which one of the following is an example of doubly magic nuclei

[Question ID = 6685]
1. 18O

[Option ID = 26734]
2. 48Ca

[Option ID = 26735]
3. 124Sn

[Option ID = 26736]
4. 204Pb

[Option ID = 26737]

48Ca

[Option ID = 26735]

14) Which radiation has maximum ionization power?
[Question ID = 6686]
1. Alpha [Option ID = 26738]
2. Beta [Option ID = 26739]
3. Neutron [Option ID = 26740]
4. Gamma [Option ID = 26741]

Alpha [Option ID = 26738]

15) For beta‐minus decay, which statement is TRUE?
[Question ID = 6688]
1. Daughter nuclide atomic mass (AD) is more than that of the parent nuclide atomic mass (Ap ) [Option ID = 26746]
2. Daughter nuclide atomic number (ZD) is same that of the parent nuclide atomic number (Zp ) [Option ID = 26747]
3. Daughter nuclide neutron number (ND) is less than that of the parent nuclide neutron number (Np ) [Option ID = 26748]
4. Daughter nuclide neutron number (ND) is same that of the parent nuclide neutron number(Np ) [Option ID = 26749]

Daughter nuclide neutron number (ND) is less than that of the parent nuclide neutron number (Np ) [Option ID = 26748]

16) The probability that student A solves the problem is 1/2, and that of B is 2/3. What is the probability that the problem
is solved?

[Question ID = 6689]
1. 4/6

[Option ID = 26750]
2. 1/3

[Option ID = 26751]
3. 5/6

[Option ID = 26752]
4. none of these

[Option ID = 26753]

5/6

[Option ID = 26752]

17) Are the three points whose position vectors are 2i+3j‐4k, i‐2j+3k and ‐7j+10k collinear?

[Question ID = 6690]
1. Yes

[Option ID = 26754]
2. No

[Option ID = 26755]
3. Cannot be determined

[Option ID = 26756]
4. None of these

[Option ID = 26757]

Yes

[Option ID = 26754]

18) The number of independent fundamental solutions in n‐th order ordinary differential equation is
[Question ID = 6692]
1. n‐1 [Option ID = 26762]
2. n [Option ID = 26763]
3. n+1 [Option ID = 26764]
4. 2n [Option ID = 26765]

n [Option ID = 26763]

19) If and then find

[Question ID = 6693]
1. ‐5/26‐6i/13

[Option ID = 26766]
2. ‐5/26+6i/13

[Option ID = 26767]
3. 8+18i

[Option ID = 26768]
4. 8‐18i

[Option ID = 26769]

‐5/26‐6i/13

[Option ID = 26766]

20)
The rank of the following matrix is

[Question ID = 6699]
1. 1

[Option ID = 26790]
2. 2

[Option ID = 26791]
3. 3

[Option ID = 26792]
4. 4

[Option ID = 26793]

2

[Option ID = 26791]

21) Two Carnot engines X and Y are operating in series. The engine X receives heat at 1200 K and rejects to a reservoir at
a temperature T. The second engine Y receives the heat rejected by X and in turn rejects to a heat reservoir at 300 K.
Calculate the temperature T (in Kelvin) for the situation when the efficiency of the engines is same
[Question ID = 6704]
1. 600 K [Option ID = 26810]
2. 750 K [Option ID = 26811]
3. 0 [Option ID = 26812]
4. 450 K [Option ID = 26813]

600 K [Option ID = 26810]

22) A square conducting loop of mass m, side l and resistance R is dropped into a region with a uniform horizontal magnetic

field B whose direction is perpendicular to the plane of the falling loop. The loop will reach a terminal velocity given by

[Question ID = 7330]

1.

[Option ID = 29314]

2.

[Option ID = 29315]

3.

[Option ID = 29316]
4. None of these

[Option ID = 29317]

[Option ID = 29314]

23) An ideal inductor, a resistor of resistance R Ohms and a capacitor with adjustable capacitance are connected in series
to an alternating voltage with an effective value of V Volts and with frequency of f Hz. The current flowing through the
circuit when the capacitance of the capacitor is set to C1 is the same as when the capacitance of the capacitor is set to C2,
. The inductance of the inductor L is given by

[Question ID = 7331]

1.

[Option ID = 29318]
2.

[Option ID = 29319]

3.

[Option ID = 29320]

4.

[Option ID = 29321]

[Option ID = 29318]

24) A cylinder of length L is made up of an inner core of steel of radius r1 and an outer sheath of copper of thickness r1.
The resistivities of steel and copper are and respectively. The total resistance of the cylinder is

[Question ID = 7332]

1.

[Option ID = 29322]

2.

[Option ID = 29323]

3.

[Option ID = 29324]
4. Cannot be determined from the information provided above

[Option ID = 29325]

[Option ID = 29322]

25) A meter stick is at an angle of 45° to the x' axis in its rest frame. The rod moves with a speed of along the
direction w.r.t. a frame S. The length of the rod in S is

[Question ID = 7333]

1.

[Option ID = 29326]

2.

[Option ID = 29327]

3.

[Option ID = 29328]

4.

[Option ID = 29329]

[Option ID = 29326]

26) An AC generator with output and frequency f is connected to the plates of an air filled parallel plate capacitor of plate
area A and plate separation d. The maximum value of the displacement current is

[Question ID = 7334]

1.

[Option ID = 29330]

2.

[Option ID = 29331]

3.

[Option ID = 29332]
4. Cannot be determined from the information provided

[Option ID = 29333]

[Option ID = 29330]

27) An electron enters a uniform magnetic field of flux density 1.2 Wb/m2. Find the energy difference in (eV), between
electrons having spins parallel and anti‐parallel to the field. (Given: J/T)

[Question ID = 7335]
1. 3 .95 x 10‐5 eV

[Option ID = 29334]
2. 13.95 x 10‐5eV

[Option ID = 29335]
3. 23.95 x 10‐5 eV

[Option ID = 29336]
4. 33.95 x 10‐5 eV

[Option ID = 29337]

13.95 x 10‐5eV

[Option ID = 29335]

28) Using the vector atom model, determine the possible values of the angular momentum of an electron in f‐ shell

[Question ID = 7336]
1.

[Option ID = 29338]
2.

[Option ID = 29339]
3.

[Option ID = 29340]
4.

[Option ID = 29341]

[Option ID = 29338]

29) The two eigenvalues of the matrix are

[Question ID = 7337]
1. 2,0

[Option ID = 29342]
2. 1,1

[Option ID = 29343]
3. 1,2

[Option ID = 29344]
4. 0,1

[Option ID = 29345]

2,0

[Option ID = 29342]

30) The commutator, , is equal to

[Question ID = 7338]
1. ihx

[Option ID = 29346]
2. 2ihx

[Option ID = 29347]
3. 2ihpx

[Option ID = 29348]
4. Zero

[Option ID = 29349]

ihx

[Option ID = 29346]

31)

[Question ID = 7339]
1.

[Option ID = 29350]

2.

[Option ID = 29351]

3.

[Option ID = 29352]

4.

[Option ID = 29353]

[Option ID = 29350]

32)

[Question ID = 7340]
1. 0.96 [Option ID = 29354]
2. ‐ 0.32 [Option ID = 29355]
3. 0 [Option ID = 29356]
4. 0.75 [Option ID = 29357]

0.96 [Option ID = 29354]

33) The primitive translation vector of a two‐dimensional lattice are , . The primitive translation vector of
its reciprocal lattice in x‐direction is given by

[Question ID = 7341]
1.

[Option ID = 29358]
2.

[Option ID = 29359]
3.

[Option ID = 29360]
4.

[Option ID = 29361]

[Option ID = 29358]

34) The mean drift speed of an electron in an applied electric field E with electron density ‘n’ can be expressed as

[Question ID = 7342]
1.

[Option ID = 29362]
2.

[Option ID = 29363]
3.

[Option ID = 29364]
4. none of these

[Option ID = 29365]

[Option ID = 29362]

35) An un‐damped oscillator has time period sec. Now a little damping is added so that its time period changes to
sec. By what factor will the amplitude of oscillation decrease after 10 cycles?

[Question ID = 7343]
1.

[Option ID = 29366]
2.

[Option ID = 29367]
3.

[Option ID = 29368]
4. None of these

[Option ID = 29369]

[Option ID = 29366]

36) A kilogram of water has a constant heat capacity of 4.2 kJ/K/kg over the temperature range 0°C to 100° C. The water
was initially at 0° C and is brought into contact with a heat reservoir at 100° C. When the water is in thermal equilibrium
with the heat reservoir calculate the change in entropy of the universe (Water + Reservoir).

[Question ID = 7344]
1. J/K

[Option ID = 29370]
2. J/K

[Option ID = 29371]
3. J/K

[Option ID = 29372]
4. 1310.8 J/K

[Option ID = 29373]

J/K

[Option ID = 29370]

37) Two identical finite bodies of constant volume and of constant heat capacity at constant volume Cv, are used to drive a
heat engine. Their initial temperatures are T1 and T2. The maximum amount of work which can be obtained from the
system is

[Question ID = 7345]
1.

[Option ID = 29374]
2.

[Option ID = 29375]
3.

[Option ID = 29376]
4. 0

[Option ID = 29377]

[Option ID = 29374]

38) For a system of bosons, we can write the Bose‐Einstein distribution function as , Where,
and (kB = Boltzmann constant). If μ represents the chemical potential, then which one of the following is true?

[Question ID = 7346]
1.

[Option ID = 29378]
2.

[Option ID = 29379]
3.

[Option ID = 29380]
4.

[Option ID = 29381]

[Option ID = 29379]

39) An ideal capacitor C is charged to a voltage Vo and connected at t = 0 across an ideal inductor L (The circuit now
consists of a capacitor and an inductor only). If the resonant frequency

, the voltage across the capacitor at time t > 0 is given by
[Question ID = 7347]
1. Vo [Option ID = 29382]
2. Vo cos(ωot) [Option ID = 29383]
3. Vo sin(ωot) [Option ID = 29384]
4.

[Option ID = 29385]

Vo cos(ωot) [Option ID = 29383]

40) Magnetic moment of proton in terms of nuclear magneton is

[Question ID = 7348]
1.

[Option ID = 29386]
2.

[Option ID = 29387]
3.

[Option ID = 29388]
4.

[Option ID = 29389]

[Option ID = 29387]

41) Find the eigenvalues of A+4I where I is identity matrix and A =

[Question ID = 7349]
1. 1,3

[Option ID = 29390]
2. 5,7

[Option ID = 29391]
3. 4,4

[Option ID = 29392]
4. None of these

[Option ID = 29393]

5,7

[Option ID = 29391]

42)
The limit is

[Question ID = 7350]
1.

[Option ID = 29394]
2. 1

[Option ID = 29395]
3. 0

[Option ID = 29396]
4.

[Option ID = 29397]

1

[Option ID = 29395]

43)

is equal to
[Question ID = 7351]

1.

[Option ID = 29398]

2.

[Option ID = 29399]

3.

[Option ID = 29400]

4.

[Option ID = 29401]

[Option ID = 29398]

44) is equal to

[Question ID = 7352]

1.

[Option ID = 29402]

2.

[Option ID = 29403]

3.

[Option ID = 29404]

4.

[Option ID = 29405]

[Option ID = 29403]

45) Two students are working on a math problem. The first student has probability ½ of solving it and the second student
has probability ¾ of solving it. What is the probability that at least one of them solves the problem?
[Question ID = 7353]
1.

[Option ID = 29406]

2.

[Option ID = 29407]
3.

[Option ID = 29408]

4.

[Option ID = 29409]

[Option ID = 29408]

46) Expansion of the function in the region defined by is

[Question ID = 7354]
1.

[Option ID = 29410]
2.

[Option ID = 29411]
3.

[Option ID = 29412]
4.

[Option ID = 29413]

[Option ID = 29411]

47) The Fourier transformation of the function

is

[Question ID = 7355]

1.

[Option ID = 29414]

2.

[Option ID = 29415]

3.

[Option ID = 29416]

4.

[Option ID = 29417]

[Option ID = 29414]

48) The Laplace transformation of the function is

[Question ID = 7356]
1.

[Option ID = 29418]

2.

[Option ID = 29419]

3.

[Option ID = 29420]

4.

[Option ID = 29421]

[Option ID = 29419]

49) Consider a collection of non‐interacting particles, each of mass m in a volume where the gravitational force is a –ve (z‐
direction). Consider the system is in thermal equilibrium at a temperature T. Find the partition function
[Question ID = 7357]

1.

[Option ID = 29422]

2.

[Option ID = 29423]

3.

[Option ID = 29424]

4.

[Option ID = 29425]

[Option ID = 29422]

50) The quantum distribution function for any gas atom which follows MB, BE and FD statistics is given as a generalized
single form

If the distribution function follows the MB statistics in a classical limit then what will be the condition of the following.
Symbols have their usual meanings
[Question ID = 7358]

1.

[Option ID = 29426]
2.

[Option ID = 29427]

3.

[Option ID = 29428]

4.

[Option ID = 29429]

[Option ID = 29427]