There is no definite end to earths atmosphere, but technically the border between the outer space and earth gets thinner as you move up from the earths surface. The Karman line is the closest definition there is which describes the end of the earth's atmosphere, it is 100 km above earth's sea level at approximately 1.56 % of total earth's radius. This describes the boundary between the outer space and the atmosphere.
Despite current has a magnitude and a direction, like vectors, it is a scalar because it doesn't obey laws of vector addition. For instance, if we consider a junction of

in a circuit, and two currents entering this junction, we know that the resultant current is just the algebraic sum of the two currents, not the vector sum, so it is not a vector quantity.
FOLLOW ME FOR CLEARING YOUR NEXT DOUBT
Potential energy is highest when the car is released at the top of the ramp. The correct answer is option C
Potential energy is the energy possessed by a body when the body is at rest. Potential energy is at time called gravitational potential energy which as a product of mass of the body, acceleration due to gravity and the height attained by the body. That is,
P.E = mgh
When a car is moving down a ramp, the potential energy of the car can never remain the same except the car stop at a certain point.
Whenever a car is moving down a ramp, the potential energy of the car will be highest when the car is release at the top of the ramp. And lowest when the car reaches the bottom of the ramp.
The statement that is correct about the potential energy of a car moving down a ramp is:
Potential energy is highest when the car is released at the top of the ramp.
Therefore, the correct answer is option C
Learn more here: brainly.com/question/17400615