Physics MCQs

Notes:
Gravitational force is weakest among all the fundamental forces of the nature where as the range of gravitational force is infinite.

Notes:
Those materials which do not allow any light to pass through them are called opaque materials. An opaque object stops the light completely so an opaque object casts a Dark Shadow behind it. Those materials which allow only some light to pass through them are called translucent materials. A translucent object stops the light partially. So a translucent object casts a weak shadow (less Dark Shadow). A transparent object does not stop any light from passing through it, so a transparent material does not cast any Shadow behind it.

Notes:
The term energy is used to describe the capacity of a system to do work on another system. Energy of all types (Surface tension, Kinetic, Potential etc.) have the same dimension and unit as that of work with same dimensional formula of M¹L²T^-2. In the SI system, both have the same units of Newton meter.

Notes:
As per the question, the rubber ball rebounds while the metal ball does not. So if m and v be the mass and velocity respectively, the change in momentum of rubber ball = 2 mv (in magnitude) However, the change in momentum of the metal ball = mv The rubber ball suffers almost twice the change in momentum as experienced by the metal ball.

Notes:
G = [M¹ L¹ T^-2] × [M⁰ L¹ T⁰]² × [M¹ L⁰ T⁰]^-1 × [M¹ L⁰ T⁰]^-1 = M^-1 L³ T^-2. So, dimensional formula for universal gravitational constant is [M^-1 L³ T^-2].

Notes:
If no air resistance is present, the rate of descent depends only on how far the object has fallen, no matter how heavy the object is. This means that two objects will reach the ground at the same time if they are dropped simultaneously from the same height. This statement follows from the law of conservation of energy.

Notes:
A dimensionless quantity is simply a quantity that has no units and therefore no dimensions. A ratio between two numbers is a non-dimensional or dimensionless quantity. Strain which is defined as change in dimension over original dimension has no dimensional formula. So, it is a dimensionless quantity.

Notes:
Speed is a scalar quantity that measures the rate at which an object changes its position. It refers only to how fast an object is moving, without any information about the direction. On the other hand, momentum, displacement, and torque are all vector quantities. They require both a magnitude and direction to fully describe them. Therefore, out of the options, speed is the one that is not a vector quantity.

Notes:
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. In general, it’s main function is to convert kinetic friction into rolling friction. It achieves this by using at least two races to contain the balls and transmit the loads through the balls.

Notes:
A metal to be used as a material for cooking utensils should have thermal conductivity and have to be resistant to corrosion i. e. acidic or basic contents of food.