Ray Optics and Optical Instruments — Physics STD 12 Science — Question

Two current carrying loops of same area but of different materials have same current flowing in them in anti-clockwise direction. if a magnetic field is applied in upward direction then potential energy of loop 1 and loop 2 will always be:

An electron moves with a constant velocity v in a uniform magnetic field B, parallel to the direction of the magnetic field. The force acting on electron is:

If ionisation energy of hydrogen atom in ground state is 13.6 eV , then ionisation energy of first excited state will be :

Like charges ____ each other.

One conducting U tube can slide inside another as shown in figure, maintaining electric contacts between the tubes. The magnetic field B is perpendicular to the plane of the figure. If each tube moves towards the other at a constant speed v, then the emf induced in the circuit in terms of B, l and v where l is the width of each tube, will be

What is increased in step-down transformer

(a) Voltage

(b)  Current

(c) Power

(d) Current density

Which of the following statements is not correct?

The SI value of electrical conductivity of free space or vacuum is: