Explanation:
Given that,
Length of gold wire, l = 4 m
Voltage of battery, V = 1.5 V
Current, I = 4 mA
The resistivity of gold, 
Resistance in terms of resistivity is given by :

Also, V = IR
So,

A is area of wire,
, r is radius, r = d/2 (diameter=d)

Out of four option, near option is (C) 17 μm.
Answer:
Stars are born within the clouds of dust and scattered throughout most galaxies. Deep within these clouds, turbulence creates knots with enough mass to cause the gas and dust to collapse under its own gravitational force.
Answer:
Explanation:
A mass of 700 kg will exert a force of
700 x 9.8
= 6860 N.
Amount of compression x = 4 cm
= 4 x 10⁻² m
Force constant K = force of compression / compression
= 6860 / 4 x 10⁻²
= 1715 x 10² Nm⁻¹.
Let us take compression of r at any moment
Restoring force by spring
= k r
Force required to compress = kr
Let it is compressed by small length dr during which force will remain constant.
Work done
dW = Force x displacement
= -kr -dr
= kr dr
Work done to compress by length d
for it r ranges from 0 to -d
Integrating on both sides
W = 
= [ kr²/2]₀^-4
= 1/2 kX16X10⁻⁴
= .5 x 1715 x 10² x 16 x 10⁻⁴
= 137.20 J
Vapor pressure<span> or equilibrium </span>vapor pressure<span> is defined as the </span>pressure<span> exerted by a </span>vapor<span> in thermodynamic equilibrium with its condensed phases at a certain temperature. It is independent with atmospheric pressure since it does not change by changing the atmospheric pressure only. </span>
Answer:
12 units
Explanation:
Original F = C q1q2/r^2 now change the parameters
New F = C 1/3 q1 2 q2 / (2r)^2
= 2/12 C q1q2/r^2 <=======the new force is 1/6 of original
1/6 * 72 = 12 units