CHAPTER 1 SEM 1

Which of the following are the base units of work?

• kgms^-2

• kg²m²s^-2

• kgm²s²

• kgm²s^-2

Answer explanation

D

W = Fs

Unit of work , W = Nm = (kgms^-2) m

= kgm²s^-2

Which of the following physical quantities has the dimensions ML²T^-2?

• Power

• Torque

• Stress

• Pressure

Answer explanation

unit of torque = Nm = kgm²s^-2

[torque] = ML²T^-1

Figure show two forces of 150 N and 200 N acting on a point, P. The magnitude of the resultant force at P is

• 218 N

• 338 N

• 345 N

• 350 N

Which of the following is true concerning error in measurement?

• Zero error is a random error

• Accurate measurement is the measurement in which its random error is large

• Systematic error may be caused by wrongly calibrated measuring instrument

• Random error cannot be reduced by repeated measurement of a reading

Answer explanation

Wrongly calibrated measuring instrument deviates either always positively or always negatively from the actual value

Which of the following are vector quantities only?

• Electric potential, displacement, temperature

• Electric charge, force, momentum

• Electric field strength, magnetic flux density, velocity

• work, torque, acceleration

Farad is defined as electric charge per unit potential difference. Express farad in terms of base units.

Which of the following statement is correct?

• In the measurement of the diameter of a sphere, taking more readings and finding the average value of these readings will help to reduce the systematic error of the diameter

• Plotting a graph of voltage against current readings for an ohmic device and using its gradient to find resistance will increase the error estimation

• Measuring the period of a large number of oscillations will help to reduce the error of the period

• Checking for zero error on a voltmeter before measuring a voltage will help to reduce random error

Answer explanation

For a larger number of oscillations, the error for period measurement will be reduced

• 50 J

• 150 J

• 300 J

• 500 J

          In an experiment, a student measures the external diameter, D, and the internal diameter, d, of a plastic tube. The measurement is as below.

D = (50.0 ± 0.2) mm

 d = (48.0 ± 0.2) mm

What is the thickness of the tube? 

• (1.0 ± 0.1) mm

• (1.0 ± 0.2) mm

• (2.0 ± 0.1) mm

• (2.0 ± 0.2) mm