Physics MCQ 1 PDF

Question Bank of MCQs Subject: Physics-1 Semester: 1st Paper Code: BS-PH 101 Discipline: CSE /CSBS /ME Questions of marks 1 Q1. Va...

Question Bank of MCQs Subject: Physics-1 Semester: 1st Paper Code: BS-PH 101 Discipline: CSE /CSBS /ME Questions of marks 1 Q1. Value of ∇ × 𝑟 is (a) 0 (b) 1 (c) -1 (d) 3 Q2. For a simple pendulum of constant length, the degrees of freedom will be (a) 3 (b) 0 (c) 1 (d) 2 Q3. For any vector A, if ∇ ∙ 𝐴 = 0 then A is called (a) solenoid (b) irrotational (c) solenoidal (d) rotational Q4. A particle moving on the surface of a sphere (of radius ‘𝑎’) having the constraint equation 𝑟 ≥ 𝑎, is (a) holonomic constraint (b) rheonomic constraint (c) non-holonomic constraint (d) scleronomic constrain Q5. The angle between ∇φ and the surface 𝜑 = 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 is 𝜋 𝜋 (a) zero (b)  (c) 2 (d) 4 Q6. Total angular momentum of a system is conserved, if (a) Total torque acting on the system is zero (b) Resultant force acting is zero (c) Total centripetal force has a net value (d) Total torqueacting on the system has non-zero value Q7. Degrees of freedom of a system of 𝑁 particles having 𝐾 constraints and moving in space (a) 3𝐾 − 𝑁 (b) 3(𝑁 − 𝐾) (c) 3𝑁 − 𝐾 (d) 2𝑁 − 𝐾 Q8. Frictional force is an example of (a) pseudo force (b) non-conservative force (c) periodic driving force (d) conservative force Q9. A fluid with velocity 𝑣 is said to be incompressible when (a) ∇. v = 0 (b) ∇ × 𝑣 = 0 (c) ∇. v = −1 (d) ∇ × 𝑣 = 𝐶𝑜𝑛𝑠𝑡𝑎𝑛𝑡 Q10. For a particle executing S.H.M the phase difference between displacement and acceleration is 𝜋 (a) 2 (b) π (c) 0 (d) 1.5𝜋 Q11. The potential energy of a particle executing SHM of amplitude 𝐴 is equal to its kinetic energy when the displacement of the particle is, (𝑎) ± 𝐴 2 𝑏 ± 𝐴/2 𝑐 ± 𝐴/ 2 𝑑 ± 𝐴/ 3 Q12. The motion of a particle is given by 𝑥 = 𝐴𝑠𝑖𝑛 𝜔𝑡 + 𝐵𝑐𝑜𝑠 (𝜔𝑡). The motion of the particle is simple harmonic with amplitude (𝐴+𝐵) (𝐴+𝐵) (a) (A+B) (b) (c) 𝐴2 + 𝐵 2 (d) (𝐴−𝐵) 2 Q13. When a vibrating system is subjected to a force F = Fo sin ωt, it is said to be in a state of (a) Natural vibration (b) Forced vibration (c) Thermal vibration (d) Damped vibration Q14. For critical damping the motion is (a) Oscillatory (b) non-oscillatory (c) periodic (d) circular Q15. Ghost lines in grating spectra appear due to (a) regular arrangement of slits (b) irregular arrangement of rulings (c) interference from many slits (d) polarization from many slits Q16. A diffraction pattern is obtained with a plane transmission grating using a beam of red light. What happens after red light is replaced by blue light? a) the lines will shift towards the lower angles b) the lines will disappear c) the lines will shift towards the higher angles d) no visible change will be there Q17. When a white light is incident on a plane diffracting grating the central maxima will be (a) white (b) yellow (c) black (d) dark Q18. In a grating, as N increases, the intensity of secondary maxima relative to principal maxima (a) increases (b) decreases (c) remains constant (d) vary randomly Q19. In Fraunhofer diffraction, the distance of the source and that of the screen is (a) both are finite (b) first one is finite and second one is infinite (c) first one is infinite and second one is finite (d) both are infinite Q20. Polarization conclusively proves that light waves are (a) longitudinal (b) progressive (c) stationary (d) transverse Q21. In a quarter wave plate the phase difference between O-ray and E-ray is 𝜋 𝜋 𝜋 a) 4 b) 2 c) 3 d)  Q22. When an elliptical polarized light passes through a quarter wave plate then, the emergent light be (a) elliptical polarized (b) circular polarized (c) plane polarized (d) unpolarized Q23. When a plane polarized light is incident on a quarter wave plate with its vibration making an angle of 45º with the optic axis, the emergent light is (a) elliptical polarized (b) circular polarized  (c) Plane polarized (d) partially plane polarized Q24. When elliptically polarized light, after passing through quarter wave plate, is observed through a rotating Nicol, the emergent light would have shown (a) the variation of intensity with minimum not zero (b) no variation in intensity (c) the variation of intensity with minimum zero (d) the intensity of incident and emergent light is same Q25. In gas laser, population inversion is generally created by (a) optical pumping (b) electric discharge (c) magnetic field (d) chemical reaction Q26. Ratio of Einstein’s A and B coefficient is proportional to (a) 4 (b) 3 (c) 2 (d) Q27. Which of the statesmen is not true (a) spontaneous emission is random in character having various wavelengths (b) stimulated emission can develop chain reaction leading to amplification of light (c) the laser light is highly incoherent (d) stimulated emission rate of emission is proportional to both the number of atoms in the excited state and incident intensity Q28. In comparison to the conduction current, the displacement current through a conductor, is a) less b) more c) equal d) negligible Q29.Displacement current arises due to a) positive charge only b) negative charge only c) time varying electric field d) magnetic monopole Q30. The displacement current density JD is given by 𝜕𝐸 𝜕𝐸 𝜕𝐸 𝜕𝐸 a) b) 𝜀 𝜕𝑡 c) 𝜇 𝜕𝑡 d) 𝜀𝜇 𝜕𝑡 𝜕𝑡 Q31.Ampere's law is valid only in a) time varying state b) steady state c) both time varying and steady state d) non-steady state Q32. The unit of displacement current is a) Coulomb b) Ampere c) Ampere/m2 d) Volt Q33. Example of em wave is a) sound wave b) wave in stretched string c) γ- ray d) matter wave Q34. ∇ ∙ 𝐵 = 0 imply  (a) magnetic dipole does not exist (b) magnetic field does not exist (c) magnetic monopole does not exist (d) magnetic domain does not exists Q35. In vacuum, electric susceptibility is (a) greater than 1 (b) zero (c) less than 1 (d) infinity Q36. The dimension of polarizability in SI unit is (a) F.m2 (b) F.m (c) F.m-1 (d) F.m-2 Q37. With increasing temperature, the dipolar Polarizability (o) (a) increases (b) decreases (c) remain same (d) tends to infinite Q38. A material which magnetizes to a small extent in the opposite direction to the applied external magnetic field is (a) diamagnetic material (b) paramagnetic material (c) ferromagnetic material (d) anti-ferromagnetic material Q39. The spin magnetic moments of neighbouring atoms of a ferromagnetic substance are (a) random (b) perpendicular (c) anti-parallel (d) parallel Q40. The relative permeability of a substance is 0.99. The substance is (a) Dielectric (b) diamagnetic (c) semiconductor (d) ferromagnetic Questions of marks 2      Q1.Divergence of A  3x  xy iˆ  5 xy  xz ˆj  ( xyz  yz ) kˆ at (1,2,1) is 2 2 3 (a) 50 (b) 36 (c) 29 (d) 0 Q2. The directional derivative of 𝜙 = 𝑥 2 𝑦𝑧 + 4𝑥𝑧 2 at (1, −2, −1) in the direction of the vector 2𝑖 − 𝑗 − 2𝑘 is (a) 27/5 (b) 37/3 (c) 17/4 (d) 33/7 Q3. The moment of inertia of a solid sphere about an axis passing through itscentre is 2/5 MR2. The moment of inertia about an axis tangent to the sphere is (a)3/5 MR2 (b) 7/5 MR2 (c) 1/2 MR2 (d)5/7 MR2 Q4. In a LCR series circuit, 𝐿 = 0.5𝐻 and 𝐶 = 5𝜇𝐹. Find the maximum value of 𝑅 for the motion to be oscillatory, 𝑎 632.45Ω 𝑏 855.73Ω 𝑐 516.11Ω 𝑑 112.48Ω Q5. The amplitude of oscillation of an underdamped system decreases to 20% of initial value after 5 consecutive cycles of oscillation. The logarithmic decrement is, (a) 1.46 (b)0.4 (c) 0.662 (d) 0.723 Q6. In a series L-C-R circuit,𝑅 = 10 ohm, 𝐿 = 10 mH and 𝐶 = 1𝜇𝐹. The Q value of the circuit is, (a) 15.2 (b) 22.5 (c) 10 (d) 13.6 𝜋 Q7. The equation of motion of a particle in SHM is, 𝑦 = 5 sin 3𝜋𝑡 + 3 cm. The maximum velocity of the particle is, 5 15𝜋 (a) cm/sec (b) 15𝜋 cm/sec (c) 5𝜋 cm/sec (d) cm/sec 2 2 Q8. The angle between two surface x2+y2+z2 = 9 and x2+y2- z = 3 at (2, -1, 2) is (a) 32ο (b) 78ο (c) 44ο (d) 54ο    Q9. If F   (x  y  z  3xyz) , then   F is 3 3 3 (a) 6 (x + y + z) (b) 2x + 3y2 + z (c) x+4y + z (d) x +y + z Q10. A force 𝐹 = 3𝑖 + 2𝑗 − 4𝑘 is applied at the point (1, -1,2). The torque (moment of F) about (2, -1, 3) is (a) 2𝑖 − 7𝑗 − 2𝑘 (b) 𝑖+𝑘 (c) 2𝑖 − 5𝑗 + 2𝑘 (d) 𝑖 − 7𝑗 − 𝑘 Q11. Light of 𝜆 = 5000 Å falls on the grating normally. Two adjacent principal maxima occur at sin 𝜃 = 0.2 and sin 𝜃 = 0.3 respectively. The length of the grating element is, (a) 3 × 10−3 cm (b) 3 × 10−4 cm (c) 5 × 10−4 cm (d) 4.2 × 10−5 cm Q12. If in a double slit diffraction, the fourth order maximum is missing then, (a) the slit separation is 4 times the slit width (b) the slit separation is 3 times the slit width (c) the slit width is 3 times the slit separation (d) the slit width is 4 times the slit separation Q13. When sunlight falls on the surface of water at an angle of 53𝑜 , the reflected light is found to be completely plane polarized. The angle of refraction is, (a) 37𝑜 (b) 42𝑜 (c) 60𝑜 (d) 90𝑜 𝐸0 Q14.The X and Y components of the electric field are 𝐸𝑥 = 𝐸0 cos 𝜔𝑡 + 𝑘𝑧 and 𝐸𝑦 = cos 𝜔𝑡 + 𝑘𝑧 + 𝜋. 2 The angle that the resultant field makes with the X axis is,  1 1 1 1 (a) 𝑡𝑎𝑛−1 − (b) 𝑡𝑎𝑛−1 (c) 𝑡𝑎𝑛−1 (d) 𝑡𝑎𝑛−1 − 2 3 2 3 Q15.The thickness of a calcite plate which would convert plane polarized light into circularly polarized light is [Given µo = 1.652 and µe = 1.593, λ = 6000 Å]. (a) 578.6 nm (b) 2071.7 nm (c) 1335.8 nm (d) 2542 nm Q16.Two polaroids are so adjusted that the intensity of light is maximum after passing through these polaroids. The angle through which one polaroid be rotated to reduce the intensity to one-fourth is, (a) 60 (b) 38.63 (c) 27.5 (d) 52 Q17. For a two-level system, the ratio of population of the higher energy state to the population of the lower energy state is equal to 1/e. If the wavelength of the radiation emitted due to transition is 6000 Å then the temperature of the system is, (a) 1672K (b) 2400 K (c) 950K (d)24007 K Q18. A clear sheet of polarized film is placed on the top of a similar sheet so that their axes make an angle of 300 with each other. The ratio of intensity of the emergent light to that of unpolarized incident light is (a) 1: 3 (b) 1:4 (c) 3:8 (d) 3:4 Q.19 Two Nicol prisms are crossed to each other. Now, one of them is rotated through 60. What percentage of incident unpolarized light will pass through the system? (a) 12.5 % (b) 37.5% (c) 25% (d) 75 % Q20. The population of two states in a He-Ne laser that produces a light of wavelength 632.8 nm at 27º C is (a) 1.2 × 10-33 (b) 3.9 × 10-33 (c) 5.7 × 10-33 (d) 7.4 × 10-33 Q21. Capacitance of a parallel plate capacitor is 2 μF. The rate at which potential difference must be changed to get displacement current of 0.4 A is (a) 8 × 105 V/s ((b) 4 × 105 V/s c) 2 × 105 V/s d) 6 × 104 V/s Q22. An em wave is represented by E = E0 cos(1000x - 5000t), the wavelength of the wave is (a) 6.28 × 10-3 m b) 3.14 × 10-3 m c) 9.44 × 10-3 m d) 5.6 × 10-2 m Q23. If an electromagnetic wave propagates through a medium with relative permittivity 9 and permeability 4, the velocity of the wave is a) 8× 107 m/s b) 50× 107 m/s c) 2.5× 107 m/s d) 5× 107 m/s Q24. Helium gas is placed in an electric field of 6×105 V/m. The polarizability of helium is 2.33×10-41 F m2 and the density of helium is 20.6×1025 molecules/m3. The induced dipole moment per unit volume is (a) 5.67×10-9 C/m2 (b) 2.88×10-9 C/m2  (c) 9.05×10-9 C/m2 (d) 6.94×10-9 C/m2 Q25. If a material is magnetised with magnetisation 3380 A/m for a flux density 0.0048 Wb/m 2, the magnetic field intensity is (a) 44 A/m (b) 441 A/m (c) 401 A/m (d) 144 A/m Q26.The susceptibility of a paramagnetic material is 0.87×10-4.The magnetisation of the material placed in an external field of 106 A/m at a temperature of 300 K will be (a) 870 A/m (b) 7.8 A/m (c) 78 A/m (d) 87 A/m Q27.A gas contains 2.7 × 1025 atoms/m3 and dielectric const. is 1.0000684. The electronic polarisability of the atom is (a) 5.3 × 10-41 Fm2(b) 9.45 × 10-41 Fm2(c) 7.20 × 10-41 Fm2(d) 2.24 × 10-41 Fm2 Q28. In the Bohr model of hydrogen atom, the electron is revolving around the nucleus in a path of radius 5 × 10-11 m at a frequency of 6.8 × 1015 rev/sec. The magnetic moment of the electron is (a) 6.9 × 10−22 A. m2 (b) 4.3 × 10−24 A. m2 (c) 8.54 × 10−24 A. m2 (d) 2.4 × 10−25 A. m2 Q29. The electronic polarisability of Ar atom having radius 10-10 m is (a) 4.15 × 10-40 F m2 (b) 3.19 × 10-40 F m2 (c) 2.57 × 10-40 F m2 (d) 1.11 × 10-40 F m2 Q30. A paramagnetic material has 1028 atoms per m3. Its susceptibility at 350 K is 2.8×10-4. The susceptibility at 300 K is, (a) 3.01×10-4 (b) 4.14×10-4 (c) 1.82×10-4 (d) 3.267×10-4