Electric Charges and Fields — Physics STD 12 Science — Question

A 25 W, 220 V bulb and a 100 W, 220 V bulb are connected in parallel across a 440 V line(a) Only 100 watt bulb will fuse(b) Only 25 watt bulb will fuse(c) Both bulbs will fuse(d) None of the bulbs will fuse

For the sustained interference of light, the necessary condition is that the two sources should(a) Have constant phase difference(b) Be narrow(c) Be close to each other(d) Of same amplitude

A metallic sphere has a charge of 10μC. A unit negative charge is brought from A to B  both 100 cm away from the sphere but  A being east of it while B being on west. The net work done is(a) Zero  (b) 2/10 joule (c) -2/10 joule  (d) -1/10 joule

We have two wires A and B of same mass and same material.  The diameter of the wire A is half of that B.  If the resistance of wire A is 24 ohm then the resistance of wire B will be(a) 12 Ohm(b) 3.0 Ohm(c) 1.5 Ohm(d) None of the above

Infrared radiation are detected by:

Which of these is a correct definition of conventional current?

The amplification produced by a triode is due to the action of(a) Filament(b) Cathode(c) Grid   (d) Plate

100 cells each of e.m.f. 5 V and internal resistance 1 ohm are to be arranged so as to produce maximum current in a 25 ohms resistance. Each row is to contain equal number of cells. The number of rows should be(a) 2 (b) 4(c) 5  (d) 10

When two bar magnets are coaxially placed at some distance from each other, then no torque works because: