CBSE physics
Sponsor Area
Using the concept of force between two infinitely long parallel current carrying conductors, define one ampere of current.
One ampere is the value of steady current which when maintained in each of the two very long, straight, parallel conductors of negligible cross section and placed one metre apart in vacuum, would produce on each of these conductors a force equal of 2 x 10-7 N/m of its length.
Sponsor Area
To which part of the electromagnetic spectrum does a wave of frequency 5 x 1019 Hz belong?
The part of the electromagnetic spectrum is X-rays.
Two equal balls having equal positive charge ‘q’ coulombs are suspended by two insulating strings of equal length. What would be the effect on the force when a plastic sheet is inserted between the two?
On inserting the plastic sheets between the two balls the force will decrease.
The electric current flowing in a wire in the direction from B to A is decreasing. Find out the direction of the induced current in the metallic loop kept above the wire as shown. 
The direction of induced current is so as to oppose the change in magnetic flux through the wire.
Why is the use of A.C. voltage preferred over D.C. voltage? Give two reasons.
The reason why AC voltage is preferred over DC is because of the following reasons:
i) AC can be transmitted with much lower energy losses as compared to DC.
ii) Alternating current can be generated easily.
Sponsor Area
Mock Test Series
Mock Test Series