JEE PYQ: Units And Dimensions Question 20
Question 20 - 2019 (10 Jan Shift 1)
The density of a material in SI unit 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:
(1) 40
(2) 16
(3) 640
(4) 410
Show Answer
Answer: (1)
Solution
Density in new system $= 128 \times \frac{(\text{1 kg})}{(\text{50 g})} \times \frac{(\text{25 cm})^3}{(\text{1 m})^3} = 128 \times \frac{1000}{50} \times \frac{15625}{1000000} = \frac{128 \times 20 \times 15625}{1000000} = 40$ units.
BETA
