Atoms — Physics STD 12 Science — Question

Which type of substance is copper?

A potentiometer has uniform potential gradient. The specific resistance of the material of the potentiometer wire is 10^–7 ohm–meter and the current passing through it is 0.1 ampere; cross-section of the wire is 10^–6 m².  The potential gradient along the potentiometer wire is

(a)  V/m

(b)   V/m

(c)  V/m

(d)  V/m

An airplane with wingspan 50m is flying horizontally with a speed of 360kmhr^-1 over a place where the vertical component of the earth's magnetic field is 2×10^-2. The potential difference between the tips of the wings would be

Dr. Gilbert tried to hold a brass rod by hand and induce static electricity in it by friction. Why did he fail?

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

The wires 1 and 2

A charge q1​ exerts a force of 45N on a charge of q₂ ​= 10^-5C located at a point 0.2m from q_1​. The magnitude of q_1​ is:

An antenna behaves as resonant circuit only when its length is

(a)	(b)
(c)	(d)  or integral multiple of

A metallic solid sphere is placed in a uniform electric field. The electric field lines follow the path(s) shown in figure as

A proton enters in a straight line in a uniform magnetic field along the field direction. How will its path and velocity change?