**MCQ Questions for Class 11 Physics Chapter 2 Units and Measurements**

**Q.1. The density of a material in SI units is 128 kg m-3 . In certain units in which the unit of length is 25 cm and the unit of mass is 50 g, the numerical value of density of the material is**(a) 40

(b) 16

(c) 640

(d) 410

## Answer

Answer: (a)**Q.2. The quantity having the same unit in all system of unit is**(a) mass

(b) time

(c) length

(d) temperature

## Answer

Answer: (b)**Q.3. The damping force on an oscillator is directly proportional to the velocity. The unit of the constant of proportionality is**(a) kg-ms

^{-1 }

(b) kg-ms

^{-2}

(c) kgs

^{-1}

(d) kg-s

## Answer

Answer: (c)**Q.4. If the value of work done is 10 ^{10} g-cm^{2} s^{-2} , then its value in SI units will be**(a) 10 kg-m

^{2}s

^{-2}

(b) 10

^{2}kg-m

^{2}s

^{-2}

(c) 10

^{4}kg-m

^{2}s

^{-2}

(d) 10

^{3}kg-m

^{2}s

^{-2}

## Answer

Answer: (d)**Q.5. The SI unit of thermal conductivity is**(a) J m

^{-1}K

^{-1}

(b) W-m K

^{-1}

(c) Wm

^{-1}K

^{-1}

(d) Jm K

^{-1}

## Answer

Answer: (c)**Q.6. Amongst the following options, which is a unit of time?**(a) Light year

(b) Parsec

(c) Year

(d) None of these

## Answer

Answer: (c)**Q.7. The ratio of the volume of the atom to the volume of the nucleus is of the order of**(a) 10

^{15}

(b) 10

^{25}

(c) 10

^{20 }

(d) 10

^{10}

## Answer

Answer: (a)**Q.8. Which of the following measurement is most precise?**(a) 5.00 mm

(b) 5.00 cm

(c) 5.00 m

(d) 5.00 km

## Answer

Answer: (a)**Q.9. A student measured the length of a rod and wrote it as 3.50 cm. Which instrument did he use to measure it?**(a) Ameter scale

(b) A vernier calliper where the 10 divisions in vernier scale matches with 9 divisions in main scale and main scale has 10 divisions in 1 cm

(c) A screw gauge having 100 divisions in the circular scale and pitch as 1 mm

(d) A screw gauge having 50 divisions in the circular scale and pitch as 1 mm

## Answer

Answer: (b)**Q.10. 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 1.276×10 ^{7}m. Compute the distance of the moon from the earth.**(a) 4.5x 10

^{9}m

(b) 3.83 x10

^{8}m

(c) 2.5 x 10

^{4}m

(d) 4 x10

^{7}m

## Answer

Answer: (b)**Q.11. A student measures the time period of 100 oscillations of a simple pendulum four times. The data set is 90s, 91s, 92s and 95s. If the minimum division in the measuring clock is 1s, then the reported mean time should be**(a) (92 ± 2)s

(b) (92 ± 5)s

(c) (92 ± 1.8)s

(d) (92 ± 3)s

## Answer

Answer: (a)**Q.12. 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.**(a) 0.88%

(b) 0.58%

(c) 0.78%

(d) 0.68%

## Answer

Answer: (b)**Q.13. The respective number of significant figures for the numbers 23.023, 0.0003 and 2.1×10 ^{-3} are**(a) 5, 1, 2 (b) 5, 1, 5

(c) 5, 5, 2 (d) 4, 4, 2

## Answer

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

(c) 5.35 and5.35 (d) 5.36 and5.34

## Answer

Answer: (d)**Q.15. 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

(a) I and IV (b) III and V

(c) I and II (d) I and V