Current Electricity — Physics STD 12 Science — Question

The conduction current is same as displacement current when source is:

The far point of a myopia eye is at 40 cm. For removing this defect, the power of lens required will be(a) 40 D   (b) – 4  D(c)  – 2.5 D(d)   0.25 D

Ratio of magnetic intensities for an axial point and a point on broad side-on position at equal distance d from the centre of magnet will be or The magnetic field at a distance d from a short bar magnet in longitudinal and transverse positions are in the ratio(a) 1 : 1(b) 2 : 3(c) 2 : 1(d) 3 : 2

Zener breakdown in a semi-conductor diode occurs when(a) Forward current exceeds certain value(b) Reverse bias exceeds certain value(c) Forward bias exceeds certain value(d) Potential barrier is reduced to zero

A charge q is moving with a velocity v parallel to a magnetic field B. Force on the charge due to magnetic field is:

Consider the two idealised systems: (i) a parallel plate capacitor with large plates and small separation and (ii) a long solenoid of length L > > R, radius of cross-section. In (i), E is ideally treated as a constant between plates and zero outside. In (ii), magnetic field is constant inside the solenoid and zero outside. These idealised assumptions, however, contradict fundamental laws as below:

An atom of nuclean change q is placed on a line. There particles A(mass = m, change = q), B(mass = 2, change =q) and C(mass = 3m, change = 3q) are shot towards the atom, a distance r away from the line and parallel to it. The particle that would be deflected the most would be?

An object is placed at 20 cm from a convex mirror of focal length 10 cm. The image formed by the mirror is(a) Real and at 20 cm  from the mirror(b) Virtual and at 20 cm  from the mirror(c) Virtual and at 20/3 cm  from the mirror(d) Real and at 20/3 cm  from the mirror