Questions
21
The surface tension of a liquid is 70 dyne/cm. In MKS system its value is?
Answer: 7 ✕ 10-2 N/m
25
The sum of the numbers 436.32, 227.2 and 0.301 in appropriate significant figures is
Answer: 664
26
The numbers 2.745 and 2.735 on rounding off to 3 significant figures will give
Answer: 2.74 and 2.74
27
You measure two quantities as A = 1.0 m ± 0.2 m, B = 2.0 m ± 0.2 m. We should report correct value for √AB as:
Answer: 1.4m ± 0.2 m
28
Young’s modulus of steel is 1.9 × 1011 N/m2. When expr essed in CGS units of dynes/cm2, it will be equal to (1N = 105 dyne, 1m2 = 104 cm2)
Answer: 1.9 × 1012
30
The mean length of an object is 5 cm. Which of the following measurements is most accurate?
Answer: 4.9 cm
31
Which of the following pairs of physical quantities does not have same dimensional formula?
Answer: Tension and surface tension
32
The equation of state of some gases can be expressed as Vander wal equation i.e.
(P + a/v2)(V – b) = RT
Where P is the pressure, V is the volume, T is the absolute temperature and a, b, R are
constants. The dimensions of ‘a’ are:
Answer: [M1L5T-2]
33
Which of the following pairs has the same dimensions?
Answer: Impulse and Momentum
34
The length and breadth of a rectangular sheet are 16.2 cm and 10.1cm, respectively. The area of the sheet in appropriate significant figures and error is
Answer: 164 ± 3 cm2
