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, ![\rho=2.44\times 10^{-8}\ \Omega-m](https://tex.z-dn.net/?f=%5Crho%3D2.44%5Ctimes%2010%5E%7B-8%7D%5C%20%5COmega-m)
Resistance in terms of resistivity is given by :
![R=\dfrac{\rho l}{A}](https://tex.z-dn.net/?f=R%3D%5Cdfrac%7B%5Crho%20l%7D%7BA%7D)
Also, V = IR
So,
![\dfrac{V}{I}=\dfrac{\rho l}{A}](https://tex.z-dn.net/?f=%5Cdfrac%7BV%7D%7BI%7D%3D%5Cdfrac%7B%5Crho%20l%7D%7BA%7D)
A is area of wire,
, r is radius, r = d/2 (diameter=d)
![\dfrac{V}{I}=\dfrac{\rho l}{\pi (d/2)^2}\\\\\dfrac{V}{I}=\dfrac{4\rho l}{\pi d^2}\\\\d=\sqrt{\dfrac{4\rho l I}{V\pi}} \\\\d=\sqrt{\dfrac{4\times 2.44\times 10^{-8}\times 4\times 4\times 10^{-3}}{1.5\times \pi}} \\\\d=18.2\ \mu m](https://tex.z-dn.net/?f=%5Cdfrac%7BV%7D%7BI%7D%3D%5Cdfrac%7B%5Crho%20l%7D%7B%5Cpi%20%28d%2F2%29%5E2%7D%5C%5C%5C%5C%5Cdfrac%7BV%7D%7BI%7D%3D%5Cdfrac%7B4%5Crho%20l%7D%7B%5Cpi%20d%5E2%7D%5C%5C%5C%5Cd%3D%5Csqrt%7B%5Cdfrac%7B4%5Crho%20l%20I%7D%7BV%5Cpi%7D%7D%20%5C%5C%5C%5Cd%3D%5Csqrt%7B%5Cdfrac%7B4%5Ctimes%202.44%5Ctimes%2010%5E%7B-8%7D%5Ctimes%204%5Ctimes%204%5Ctimes%2010%5E%7B-3%7D%7D%7B1.5%5Ctimes%20%5Cpi%7D%7D%20%5C%5C%5C%5Cd%3D18.2%5C%20%5Cmu%20m)
Out of four option, near option is (C) 17 μm.
Answer:
<h2>E. 3.95kW</h2>
Explanation:
Power is defined as the rate of workdone.
Power = Workdone/time taken
Given Workdone = Force * distance
Power = Force * distance/time taken
Power = mgd/t (F = mg)
m = mass of the sand in kg
g = acceleration due to gravity in m/s²
d = vertical distance covered in metres
t = time taken in seconds
Given m = 2000kg, d = 12m, t = 1min = 60secs, g = 9.8m/s²
Power = 2000*9.8*12/60
Power = 3920Watts
Minimum rate of power that must be supplied to this machine is 3920Watts or 3.92kW
The answer is true, is called Thermal pollotion:).
The correct answer is heterozygous.