Electric Charges and Fields — Physics STD 12 Science — Question

A charge q is placed at the centre of the open end of a cylindrical vessel (figure). The flux of the electric field through the surface of the vessel is:

While walking on ice, one should take small steps to avoid slipping. This is because smaller steps ensure:

1. Larger friction.
2. Smaller friction.
3. Larger normal force.
4. Smaller normal force.

The susceptibility of a magnetic substance is found to depend on temperature and the strength of the magnetising field. The material is a:

An air filled parallel plate capacitor has capacity C. If distance between plates is doubled and it is immersed in a liquid then capacity becomes twice. Dielectric constant of the liquid is(a) 1 (b) 2(c) 3(d) 4

Assertion : According to classical theory, the proposed path of an electron in Rutherford atom model will be parabolic.
Reason     : According to electromagnetic theory an accelerated particle continuously emits radiation.(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If assertion is false but reason is true.

Pick the correct options.

A conducting sphere of radius 10cm is charged 10μC. Another uncharged sphere of radius 20 cm is allowed to touch it for some time. After that if the sphere are separated, then surface density of charges, on the spheres will be in the ratio of(a) 1 : 4   (b) 1 : 3(c) 2 : 1    (d) 1 : 1

A nuclear reaction with positive Q value is:

The output of OR gate of two input terminals will be zero only when :