Magnetism And Matter — Physics STD 12 Science — Question

A current passes through a wire of nonuniform crosssection.
Which of the following quantities are independent of the cross-section?

A transformer is used to(a) Change the alternating potential (b) Change the alternating current(c) To prevent the power loss in alternating current flow (d) To increase the power of current source

When a comb rubbed with dry hair attracts pieces of paper. This is because the.

The photoelectric threshold wavelength for potassium (work function being 2eV ) is (a) 310 nm(b) 620 nm(c) 1200 nm(d) 2100 nm

Between the plates of a parallel plate capacitor a dielectric plate is introduced just to fill the space between the plates. The capacitor is charged and later disconnected from the battery. The dielectric plate is slowly drawn out of the capacitor parallel to the plates. The plot of the potential difference across the plates and the length of the dielectric plate drawn out is

Isotopes are atoms having(a) Same number of protons but different number of neutrons(b) Same number of neutrons but different number of protons (c) Same number of protons and neutrons(d) None of the above

An electron moving to the east in a horizontal plane is deflected towards south by a magnetic field. The direction of this magnetic field is:

For a thermocouple, the temperature of inversion is that temperature at which thermo e.m.f. is(a) Zero  (b) Maximum
 (c) Minimum(d) None of the above