Answer:
The total resistance of the wire is = 
Explanation:
Since the wires will both be in contact with the voltage source at the same time and the current flows along in their length-wise direction, the two wires will be considered to be in parallel.
Hence, for resistances in parallel, the total resistance, 

Parameters given:
Length of wire = 1 m
Cross sectional area of copper 
Cross sectional area of aluminium wire
![A_{al}= \pi( R^{2}-r^{2})\\\\ = \pi \times [ (2\times 10^{-3} )^{2}-(1\times 10^{-3} )^{2}] =9.42\times10^{-6} m^{2}\\](https://tex.z-dn.net/?f=A_%7Bal%7D%3D%20%5Cpi%28%20R%5E%7B2%7D-r%5E%7B2%7D%29%5C%5C%5C%5C%20%3D%20%5Cpi%20%5Ctimes%20%5B%20%282%5Ctimes%2010%5E%7B-3%7D%20%20%29%5E%7B2%7D-%281%5Ctimes%2010%5E%7B-3%7D%20%20%29%5E%7B2%7D%5D%20%3D9.42%5Ctimes10%5E%7B-6%7D%20m%5E%7B2%7D%5C%5C)
Resistivity of copper 
Resistivity of Aluminium 
Resistance of copper 
Resistance of aluminium 
The total resistance of the wire can be obtained as follows;


∴ The total resistance of the wire = 
Answer:
Explanation:
In linear motion, the directions of all the vectors describing the system are equal and constant which means the objects move along the same axis and do not change direction.
Answer:
The ratio of electric force to the gravitational force is 
Explanation:
It is given that,
Distance between electron and proton, 
Electric force is given by :

Gravitational force is given by :

Where
is mass of electron, 
is mass of proton, 
is charge on electron, 
is charge on proton, 



So, the ratio of electric force to the gravitational force is
. Hence, this is the required solution.
Answer:
0.25 m
Explanation:
We can solve the problem by using the lens equation:

where
f is the focal length
p is the distance of the object from the lens
q is the distance of the image from the lens
In this problem, we have
f = +20 cm=+0.20 m (the focal length is positive for a converging lens)
q = +1.0 m (the image distance is positive for a real image)
Solving the equation for p, we find

Answer:
102 kg.m/s
Explanation:
m = Mass of hammer = 12 kg
v = Final velocity = 8.5 m/s
u = Initial velocity = 0
t = Time taken = 8 ms
Force acting over a given amount of time or change in momentum is known as impulse.
Impulse

Impulse given to the nail is 102 kg.m/s