The options are missing and they are;
A) the electric force increases because the balloon loses its charge.
B) the electric force increases because the distance increases.
C) the electric force decreases because the distance increases.
D) the electric force decreases because his hair loses its charge.
Answer:
Correct answer is option C - the electric force decreases because the distance increases.
Explanation:
The formula for electric force is;
F = k•q1•q2/r²
Where;
K is coulombs constant
q1 and q2 are particle charges
r is distance
So,looking at the formula given earlier, if we increase the distance, the denominator will increase and thus the Force will decrease.
So the correct option is option C
Answer : The de-Broglie wavelength of this electron, 
Explanation :
The formula used for kinetic energy is,
..........(1)
According to de-Broglie, the expression for wavelength is,

or,
...........(2)
Now put the equation (2) in equation (1), we get:
...........(3)
where,
= wavelength = ?
h = Planck's constant = 
m = mass of electron = 
K.E = kinetic energy = 
Now put all the given values in the above formula (3), we get:


conversion used : 
Therefore, the de-Broglie wavelength of this electron, 
Explanation:
The given data is as follows.
Electric field (E) = 
Charge (e) =
C
Formula to calculate the magnitude of force is as follows.
F = qE
= 
= 
Therefore, we can conclude that magnitude of the force on a calcium ion with charge +e is
.
The correct option is D.
Lumen is used to quantify the amount of total light energy that a source is putting out in all direction, thus, it refers to luminous output of a light source. Initial lumen refers to the luminosity of a light when it was first turned on; the luminosity is highest at this point.
Answer:

Explanation:
The formula for the single-slit diffraction is

where
y is the distance of the n-minimum from the centre of the diffraction pattern
D is the distance of the screen from the slit
d is the width of the slit
is the wavelength of the light
In this problem,


, with n=2 (this is the distance of the 2nd-order minimum from the central maximum)
Solving the formula for d, we find:
