**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

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**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%

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**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

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**24. The multiplicative inverse of 4 – 3 i is :**

(A)

(B)

(C)

(D)

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**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

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**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

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**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

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**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

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**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

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**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

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**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

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**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

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**33. The value of ∫tan ^{2} x dx will be: **

(A) tan x + x + C

(B) cot x + x + C

(C) tan x – x + C

(D) cot x – x + C

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**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) 8πr^{2}T

(B) 16πr^{2}T

(C) 24πr^{2}T

(D) 32πr^{2}T

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**35. From which layer of atmosphere the radio waves are reflected **

(A) Mesosphere

(B) Troposphere

(C) Exosphere

(D) Ionosphere

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**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

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**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

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**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)

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**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

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**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

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