B. The resistance is directly proportional to length and inversely proportional to cross sectional area
Answer:
1 x 10¹⁷
Explanation:
Given data:
Radius of the earth = 6000km
Radius of an atom = 60pm
Now, how many orders is the radius of the earth larger than an atom
Solution:
To solve this problem, let us express both quantity as the same unit;
1000m = 1km
6000km = 6000 x 10³m = 6 x 10⁶m
60pm;
1 x 10⁻¹²m = 1pm
60pm = 60 x 1 x 10⁻¹²m = 6 x 10⁻¹¹m
Now;
The order:
= 1 x 10¹⁷
Answer: KE = 62.5J
Explanation:
Given that
Mass of object = 5kg
kinetic energy KE = ?
velocity of object = 5m/s
Since kinetic energy is the energy possessed by a moving object, and it depends on the mass (m) of the object and the velocity (v) by which it moves. Therefore, the object has kinetic energy.
i.e K.E = 1/2mv^2
KE = 1/2 x 5kg x (5m/s)^2
KE = 0.5 x 5 x 25
KE = 62.5J
Thus, the object has 62.5 joules of kinetic energy.
Answer:
- No, this doesn't mean the electric potential equals zero.
Explanation:
In electrostatics, the electric field
is related to the gradient of the electric potential V with :

This means that for constant electric potential the electric field must be zero:





This is not the only case in which we would find an zero electric field, as, any scalar field with gradient zero will give an zero electric field. For example:

give an electric field of zero at point (0,0,0)