Answer:
a)
The direction will be negative direction.
b)
The direction will be positive direction.
Explanation:
Given that
q1 = +7.7 µC is at x1 = +3.1 cm
q2 = -19 µC is at x2 = +8.9 cm
We know that electric filed due to a charge given as



Now by putting the va;ues
a)




The net electric field


The direction will be negative direction.
As we know that electric filed line emerge from positive charge and concentrated at negative charge.
b)
Now
distance for charge 1 will become =5.5 - 3.1 = 2.4 cm
distance for charge 2 will become =8.9-5.5 = 3.4 cm




The net electric field


The direction will be positive direction.
Answer:
At 81. 52 Deg C its resistance will be 0.31 Ω.
Explanation:
The resistance of wire =
Where
=Resistance of wire at Temperature T
= Resistivity at temperature T ![=\rho_0 \ [1 \ + \alpha\ (T-T_0\ )]](https://tex.z-dn.net/?f=%3D%5Crho_0%20%5C%20%5B1%20%5C%20%2B%20%5Calpha%5C%20%28T-T_0%5C%20%29%5D)
Where 
l=Length of the wire
& A = Area of cross section of wire
For long and thin wire the resistance & resistivity relation will be as follows

![\frac{0.25}{0.31}=\frac{1}{[1+\alpha(T-20)]}](https://tex.z-dn.net/?f=%5Cfrac%7B0.25%7D%7B0.31%7D%3D%5Cfrac%7B1%7D%7B%5B1%2B%5Calpha%28T-20%29%5D%7D)



T = 81.52 Deg C
Answer:
<u><em>Electric Potential Energy:</em></u>
The energy that is needed to move a charge against an electric firld is called Electric Potential Energy
<u><em>Electric Potential Difference:</em></u>
The amount of work done in carrying a unit charge from one point to an other in an electric field is called Electric Potential Difference.
<u><em>Relation:</em></u>
Relation between Electric potential and electrical potential energy is given by

Here PE represents Electric potential energy
and
is Electric potential difference
it means electric potential difference is the difference in electric potential energy divided by the charge.
Answer:
7.5s
Explanation:
Given parameters:
Velocity = 30m/s
Deceleration = 4m/s²
Unknown:
Time it takes for the car to come to complete rest = ?
Solution:
To solve this problem, we use the kinematics expression below:
v = u + at
Since this is a deceleration
v = u - at
v is the final velocity
u is the initial velocity
a is the acceleration
t is the time taken
v - u = -at
0 - 30 = -4 x t
-30 = -4t
t = 7.5s
Every element is able to be recognized individually in many different ways. A very easy and common way is using light absorption also known as spectroscopy. Every atom has electrons, and these electrons like to stay in their lowest-energy configuration. However, when photons collide with an electron it can increase it to a higher energy level.. This is absorption, and each element’s electrons absorb light at specific wavelengths related to the difference between energy levels in that atom. But the electrons want to return to their original levels, so they don’t hold onto the energy for long. When they emit the energy, they release photons with exactly the same wavelengths of light that were absorbed in the first place. An electron can release this light in any direction, so most of the light is emitted in directions away from our line of sight. Therefore, a dark line appears in the spectrum at that particular wavelength.
Because the wavelengths at which absorption lines occur are unique for each element, astronomers can measure the position of the lines to determine which elements are present in a target. The amount of light that is absorbed can also provide information about how much of each element is present.