Units and Measurements

A physical quantity Q is related to four observables a, b, c, d as follows : Q= ab4cd where, a=(60 3) Pa; b=(20 0.1) m; c=(40 0.2) N s m-2 and d=(50 0.1) m, then the percentage error in Q is x1000, where x= .

In a measurement, it is asked to find modulus of elasticity per unit torque applied on the system. The measured quantity has dimension of [MaLbTc]. If b = -3, the value of c is .

A tiny metallic rectangular sheet has length and breadth of 5 mm and 2.5 mm, respectively. Using a specially designed screw gauge which has pitch of 0.75 mm and 15 divisions in the circular scale, you are asked to find the area of the sheet. In this measurement, the maximum fractional error will be x100 where x is .

Match List - I with List - II. Choose the correct answer from the options given below:

1. (A)-(II), (B)-(I), (C)-(IV), (D)-(III)
2. (A)-(I), (B)-(III), (C)-(IV), (D)-(II)
3. (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
4. (A)-(III), (B)-(I), (C)-(II), (D)-(IV)

For an experimental expression y= 32.3 112527.4, where all the digits are significant. Then to report the value of y we should write

1. y=1326.186
2. y=1326.2
3. y=1326.19
4. y=1330

The least count of a screw gauge is 0.01 mm. If the pitch is increased by 75% and number of divisions on the circular scale is reduced by 50%, the new least count will be 10-3 mm.

The energy E and momentum p of a moving body of mass m are related by some equation. Given that c represents the speed of light, identify the correct equation

1. E2=pc2+m2c4
2. E2=pc2+m2c2
3. E2=p2c2+m2c4
4. E2=p2c2+m2c2

The position of a particle moving on x-axis is given by x(t)=A t+B 2t+Ct2+D, where t is time. The dimension of ABCD is

1. L
2. L3 T-2
3. L2 T-2
4. L2

The electric flux is = + where and are linear and surface charge density, respectively. ( ) represents

1. displacement
2. charge
3. electric field
4. area

The energy of a system is given as E(t)= 3e- t, where t is the time and =0.3 s-1. The errors in the measurement of and t are 1.2\% and 1.6\%, respectively. At t=5 s, maximum percentage error in the energy is :

1. 6\%
2. 11.6\%
3. 4\%
4. 8.4\%