Current Electricity — Physics STD 12 Science — Question

If two streams of protons move parallel to each other in the same direction, then they(a) Do not exert any force on each other(b) Repel each other(c) Attract each other(d) Get rotated to be perpendicular to each other

A point object is placed at a distance of 10 cm  and its real image is formed at a distance of 20 cm from a concave mirror. If the object is moved by 0.1 cm towards the mirror, the image will shift by about(a) 0.4 cm away from the mirror(b) 0.4 cm towards the mirror(c) 0.8 cm away from the mirror(d) 0.8 cm towards the mirror

A closed cubical box is completely filled with water and is accelerated horizontally towards right with an acceleration α. The resultant normal force by the water on the top of the box.

1. Passes through the centre of the top.
2. Passes through a point to the right of the centre.
3. Passes through a point to the left of the centre.
4. Pecomes zeros.

To reduce the reasonant frequency in an LCR series circuit with a generator:

 If a variable frequency ac source is connected to a capacitor then with decrease in frequency the displacement current will:

The force with which a magnet attracts objects like iron is called ....................... .

Silicon is a semiconductor. If a small amount of As is added to it, then its electrical conductivity(a) Decreases(b) Increases(c) Remains unchanged(d) Becomes zero

Biological importance of Ozone layer is

In a communication system, noise is most likely to affect the signal (a) At the transmitter(b) In the channel or in the transmission line (c) In the information source(d) At the receiver