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HOME ASSIGNMENT

1 Ampere second is a unit of
(i)current (ii)charge (iii)energy (iv)power
2 A far off planet is estimated to be at a distance D from the earth. If its diametrically opposite
extremes subtend an angle Ө at an observatory situated on the earth, the approximate diameter
of the planet is
1
(i) (ii) (iii)D (iv)
D
3 The acceleration due to gravity is measured on the surface of earth by using a simple pendulum. If
α and β are relative errors in the measurement of length and time period respectively, then
percentage error in the measurement of acceleration due to gravity is
1
(i) (α+ β)x100 (ii)( α - 2 β) (iii)(2 α + β)x100 (iv)( α + 2 β)x100
2
4 A packet contains silver powder of mass (20.23±0.01)g .Some of the powder of mass (5.75±0.01)g
is taken out from it. The mass of the powder left back is
(i) (14.48±0.00)g (ii) (14.48±0.02)g (iii) (14.5±0.1)g (iv)none of these
5 One astronomical unit is a distance equal to
8
15
11
(i)9.46 x 10 m (ii)1.496 x 10 m (iii)3 x 10 m (iv)none of these
6 1 joule of energy is to be converted into new system of units in which length is measured in 10 m.
mass in 10 kg and time in 1 minute. The numerical value of 1 J in the new system is
-4
-1
-2
-3
(i)36 x 10 (ii)36 x 10 (iii)36 x 10 (iv)36 x 10
7 Which of the following is dimensionally incorrect?
1 2 2
(i)u=v-at (ii)s-ut = at (iii)u =2a(gt-1) (iv)none of these
2
8 Which of the following relation cannot be deduced using dimensional analysis?
1 2
(i)y=A sin( t+kx) (ii)v=u +at (iii)k= mv (iv)all of these
2
9 The number of significant figures in the measured value 0.0204 is …………………..
3
10 An object of mass 4.237 g occupies a volume 1.72 cm . The density of the object to appropriate
significant figures is…………………………
-2
11 The acceleration of an object is 5 km h . Its value in SI units is ………………………………….
12 If the percentage error in the measurement of momentum and mass of an object are 2% and 3%
respectively, then maximum percentage error in the calculated value of its kinetic energy is ……....
13 An object accelerates uniformly from initial velocity u to final velocity v. It travels distance s in
time t. Then check the dimensional consistency of the following equations.
+ 1 2 2 2 2
(i) = (ii)s= ut + at (iii)v – u =

3 2
14 Consider a simple pendulum, having a bob attached to a string that oscillates under the action of
the force of gravity. Suppose that the period of oscillation of the simple pendulum depends on its
length (l), mass of the bob (m) and acceleration due to gravity (g). Derive the expression for its
time period (T) using method of dimensions.
15 What are the advantages of SI system of units?
16 What is meant by parallax?
17 The Sun’s angular diameter is measured to be 1920”. The distance D of the Sun from the Earth is
11
1.496 x 10 m. What is the diameter of the Sun?
18 The length of a rod as measured in an experiment is found to be 2.48 m, 2.46 m, 2.49 m, 2.49 m
and 2.46 m. Find the average length, the absolute error in each observation and the percentage
error.
19 The length and breadth of a rectangle are (5.7±0.1) and (3.4±0.2) . Calculate area of the
rectangle with error limits.
4 1/3
3/2
20 Find the relative error in Z, if Z= A B / CD and the percentage error in the measurements of
A,B,C and D are 4%,2%,3% and 1% respectively.