October 2022

Q. Which of the following physical quantities has different dimensions? Energy Watt hour Momentum Work Answer: Momentum

Q. Two physical quantities whose dimensions are not same, cannot be multiplied with each other divided added or substracted in the same expression added together Answer: added or substracted in the same expression

Q. The most suitable instrument for measuring the size of an atom is. Electron microscope Vernier calliper Optical Microscope Screw gauge Answer: Electron microscope

Q. Torr’ is the unit of pressure volume density flux Answer: pressure

Q.14. The numbers 5.355 and 5.345 on rounding off to 3 significant figures will give 5.35 and5.34 5.36 and5.35 5.35 and5.35 5.36 and5.34 Answer: 5.36 and5.34

Q. The respective number of significant figures for the numbers 23.023, 0.0003 and 2.1×10-3 are 5, 1, 2 5, 1, 5 5, 5, 2 4, 4, 2 Answer: 5, 1, 2

Q. Which two of the following five physical parameters have the same dimensions? I. Energy density II. Refractive index III. Dielectric constant IV. Young’s modulus V. Magnetic field I and IV III and V I and II I and V Answer: I and IV

Q. The length, breadth and height of a rectangular block of wood were measured to be l = 12.13 ± 0.02 cm, b = 8.16 ± 0.01cm and h = 3.46 ± 0.01cm. 0.88% 0.58% 0.78% 0.68% Answer: 0.58%

Q. The moon is observed from two diametrically opposite points A and B on earth. The angle θ subtended at the moon by the two directions of observation is 1°54′; given that the diameter of the earth to be about 1.276×107m. Compute the distance of the moon from the earth. 4.5x 109 m 3.83 x108