Answer:
0.009 N, repulsive
Explanation:
The electrostatic force between two electric charges is given by:

where
k is the Coulomb's constant
q1 and q2 are the two charges
r is the separation between the two charges
In this problem, we have
are the two charges
r = 4.5 m is their separation
Substituting into the equation, we find

Moreover, the force is repulsive. In fact, the following rules apply:
- When two charges have same sign, they repel each other
- When two charges have opposite signs, they attract each other
Answer:
Minimum thickness will be 100 nm
Explanation:
We have given refractive index is n = 1.5
Wavelength of the light incidence
= 600 nm
We have to find the smallest thickness of the film so that there will be minimum light reflect
For minimum thickness of non reflecting film
, here t is thickness,
is wavelength and n is refractive index
Putting all values 
So minimum thickness will be 100 nm
Answer:
Too old(Ex. if real time is 1000 then they estimate >1000)
Explanation:
This is because with time our planet may have a definite function which describes temperature.(Because of all the factors and global warming except nuclear bomb testing)
Now nuclear test on planet have significant effect on temperature rise.
Also 14°C rise in temperature is good one because of this.
If future archaeologists only consider that uniform function as above mentioned then they estimate more time then the real one.
Thus too old is right answer.
Answer:
C. both forces have the same magnitude
Explanation:
Here the action force is equal to the reaction force in accordance with the Newton's third law of motion.
Also when we apply the conservation of momentum so that the momentum bullet and the momentum of the gun are equal and according to the second law of motion by Newton, we have force equal to the rate of change in momentum.
We have the equation for momentum as:

Newton's second law is Mathematically given as:

Momentum is constant and the reaction time is equal, so the force exerted will also be equal.
Answer:
option (a)
Explanation:
To make a galvanometer into voltmeter, we have to connect a high resistance in series combination.
The voltmeter is connected in parallel combination with teh resistor to find the voltage drop across it.
An ideal voltmeter has very high resistance that means it has a resistance as infinity.