Physical World and Measurement MCQ (NEET, JEE Main) – Test 1 1

Planck’s constant (h), speed of light in vacuum (c) and Newton’s gravitational constant (G) are three fundamental constants. Which of the following combinations of these has the dimension of length? [NEET 2016]

A screw gauge with a pitch of 0.5 mm and a circular scale with 50 divisions is used to measure the thickness of a thin sheet of Aluminium. Before starting the measurement, it is found that when the two jaws of the screw gauge are brought in contact, the 45^th division coincides with the main scale line and that the zero of the main scale is barely visible. What is the thickness of the sheet if the main scale reading is 0.5 mm and the 25^th division coincides with the main scale line? [JEE MAIN 2016]

In the expression for Boyle’s law, the product ‘PV’ has dimensions of [MH CET 2015]

A screw gauge gives the following reading when used to measure the diameter of a wire.

Main scale reading : 0 mm
Circular scale reading : 52 divisions

Given that 1 mm on main scale corresponds to 100 divisions of the circular scale.
The diameter of wire from the above data is [AIEEE 2011]

A wire of length l = 6 ± 0.06 cm and radius r = 0.5 ± 0.005 cm and mass m = 0.3 ± 0.003 gm. Maximum percentage error in density is [IIT JEE 2004]