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 date is :
(1) 0.052 cm (2) 0.026 cm (3) 0.005 cm (4) 0.52 cm
A thin horizontal circular disc is rotating about a vertical axis passing through its centre. An insect is at rest at a point near the rim of the disc. The insect now moves along a diameter of the disc to reach its other end. During the journey of the insect, the angular speed of the disc:
(1) continuously decreases (2) continuously increases
(3) first increases and then decreases (4) remains unchanged
This question has Statement – 1 and Statement – 2. Of the four choices given after the statements, choose the one that best describes the two statements.
Statement-1 : Sky wave signals are used for long distance radio communication. These signals are in general, less stable than ground wave signals.
Statement-2 : The state of ionosphere varies from hour to hour, day to day and season to season.
(1) Statement-1 is true, Statement-2 is true; Statement-2 is the correct explanation of Statement-1.
(2) Statement-1 is true, Statement-2 is true; Statement-2 is not the correct explanation of Statement-1.
(3) Statement-1 is false, Statement-2 is true.
(4) Statement-1 is true, Statement-2 is false.
If a wire is stretched to make it 0.1% longer, its resistance will :
(1) increase by 0.2% (2) decrease by 0.2% (3) decrease by 0.05% (4) increases by 0.05%
Energy required for the electron excitation in Li++ from the first to the third Bohr orbit is :
(1) 36.3 eV (2) 108.8 eV (3) 122.4 eV (4) 12.1 eV