Atoms — Physics STD 12 Science — Question

The line on the earth's surface joining the points where the field is horizontal is

(a) Magnetic meridian

(b) Magnetic axis

(c) Magnetic line

(d) Magnetic equator

The line of force in a magnetic field represents the direction at each point that a magnetic needle placed at the point takes up. Do they also represent the direction of the force on a moving charge at each point?

A magnet makes 40 oscillations per minute at a place having magnetic field intensity of 0.1 × 10^–5 T. At another place, it takes 2.5 sec to complete one vibration. The value of earth’s horizontal field at that place is

(a) 0.25 × 10–6 T

(b) 0.36 × 10–6 T

(c) 0.66 × 10–8 T

(d) 1.2 × 10–6 T

For watt-less power in an AC circuit the phase angle between the current and voltage is.

In a metal, the separation between conduction band and valence band is of the order:

Two magnets A and B are identical and these are arranged as shown in the figure. Their length is negligible in comparison to the separation between them. A magnetic needle is placed between the magnets at point P which gets deflected through an angle θ  under the influence of magnets. The ratio of distance   and  will be

(a)

(b)

(c)

(d)

We get __________ current through rectifier without simple filter.

Which decay increases the atomic number?

If two soap bubbles of different radii are connected by a tube:

1. Air flows from bigger bubble to the smaller bubble till the sizes become equal.
2. Air flows from bigger bubble to the smaller bubble till the sizes are interchanged.
3. Air flows from the smaller bubble to the bigger.
4. There lis no flow of air.

For germanium diode, the junction voltage is about _____.