UKSSSC Police Head Constable (Mukhya Aarakshi) Telecommunication Exam 31 July 2022 (Official Answer Key)

21. Relation between coefficient of friction (μ) and angle of friction (θ) is :
(A) μ = cosθ
(B) μ = tanθ
(C) μ = sinθ
(D) None of the above

22. A 42 kilowatt engine is operating between 227°C and 177°C; the efficiency of the engine will be :
(A) 5%
(B) 20%
(C) 10%
(D) 15%

23. According to Bohr, the ratio of velocities of electrons in first, second and third orbit of hydrogen atom would be :
(A) 1:2:3
(B) 3:2:1
(C) 6:3:2
(D) 2:3:6

24. The multiplicative inverse of 4 – 3i is :
(A)

(B)

(C)

(D)

25. Which of the following statement is correct?
(A) Determinant is a square matrix
(B) Determinant is a number associated to a matrix
(C) Determinant is a number associated to a square matrix
(D) None of the above

26. Area of a rectangle having vertices A, B, C and D with position vectors and respectively is :
(A) ½
(B) 1
(C) 2
(D) 4

27. On increasing the intensity of light, the maximum kinetic energy of photo electrons will be:
(A) increases
(B) decreases
(C) remains unchanged
(D) none of the above

28. Kepler’s second law is a consequence of:
(A) conservation of kinetic energy
(B) conservation of linear momentum
(C) conservation of charge
(D) conservation of angular momentum

29. If the focal length of a biconvex lens in air is 10 cm. and if this lens is immersed in water (μ = 4/3), then its focal length is (refractive index of glass = 3/2):
(A) 5 cm
(B) 10 cm
(C) 20 cm
(D) 40 cm

30. Distance between the line 4x + 3y = 11 and 8x + 6y = 15 will be
(A) 7/10
(B) 5
(C) 7/4
(D) None of the above

31. If V_o and V_e are orbital velocity and escape velocity respectively, then:
(A) V_e = V_o
(B) V_o = √2 V_e
(C) V_e = V_o√2
(D) None of the above

32. On the basis of which property from the following the light waves and sound waves can be differentiated?
(A) Interference
(B) Refraction
(C) Polarisation
(D) Reflection

33. The value of ∫tan² x dx will be:
(A) tan x + x + C
(B) cot x + x + C
(C) tan x – x + C
(D) cot x – x + C

34. If the radius of a soap bubble is r. the surface tension of soap solution is T. keeping temperature constant, the radius of the soap bubble is doubled, the energy necessary for this will be
(A) 8πr²T
(B) 16πr²T
(C) 24πr²T
(D) 32πr²T

35. From which layer of atmosphere the radio waves are reflected
(A) Mesosphere
(B) Troposphere
(C) Exosphere
(D) Ionosphere

36. There are 20 teachers in a school who teach Mathematics or Physics. Out of these, 12 teach Mathematics and 4 teach Physics and Mathematics both then how many teachers teach Physics?
(A) 16
(B) 8
(C) 12
(D) 4

37. The audio frequencies range is :
(A) 20 Hz to 20,000 kHz
(B) 20 Hz to 20 kHz
(C) 20 kHz to 20,000 kHz
(D) None of the above

38. If A and B are two disjoint sets, then the value of n (A ∪ B) will be :
(A) (A) + n(B)
(B) n(A) + n(B) – n(A ∩ B)
(C) n(A) + n(B) + n(A ∩ B)
(D) n(A).n(B)

39. By increasing angle of incidence in a prism, angle of deviation (δ) changes as:
(A) Angle of deviation increases continuously
(B) Angle of deviation decreases continuously
(C) First increases, become maximum then decreases
(D) First decreases become minimum and then increases

40. When a body falls freely towards the earth, then its total energy:
(A) Increases
(B) Remains constant
(C) Decreases
(D) First increases and then decreases