Physics True or False Quiz

A physical quantity must have both magnitude and unit.

• True

• False

Answer explanation

True. A physical quantity is defined by both its magnitude (size) and its unit (measurement standard), such as meters for length or kilograms for mass. Without both, the quantity is incomplete.

Scalar quantities have both magnitude and direction.

• True

• False

Answer explanation

Scalar quantities only have magnitude, not direction. Therefore, the statement that scalar quantities have both magnitude and direction is false.

An object in motion will continue to move at the same speed and direction unless acted upon by an external force.

• True

• False

Answer explanation

The statement reflects Newton's First Law of Motion, which states that an object will remain in its state of motion unless acted upon by an external force. Therefore, the correct answer is True.

Acceleration is directly proportional to force and inversely proportional to mass.

• True

• False

Answer explanation

The statement is true because according to Newton's second law, acceleration (a) is directly proportional to the net force (F) acting on an object and inversely proportional to its mass (m), expressed as a = F/m.

A car moving in a circular path at constant speed has zero acceleration.

• True

• False

Answer explanation

The statement is false. A car moving in a circular path at constant speed experiences centripetal acceleration directed towards the center of the circle, even though its speed remains constant.

Momentum is a scalar quantity.

• True

• False

Answer explanation

Momentum is a vector quantity, not a scalar. It has both magnitude and direction, which is why the statement is false.

In a collision, the total momentum before and after the collision remains the same in an isolated system.

• True

• False

Answer explanation

The statement is True because in an isolated system, the law of conservation of momentum states that the total momentum before a collision equals the total momentum after the collision, regardless of the nature of the collision.

Pressure in a fluid increases with depth.

• True

• False

Answer explanation

True. In a fluid, pressure increases with depth due to the weight of the fluid above. This principle is described by Pascal's law, which states that pressure applied to a confined fluid is transmitted undiminished in all directions.

The unit of pressure is Newton.

• True

• False

Answer explanation

The unit of pressure is not Newton; it is Pascal (Pa). Newton is a unit of force. Therefore, the statement is false.

In a hydraulic system, a small force applied on a small piston results in a larger force on a larger piston.

• True

• False

Answer explanation

True. In a hydraulic system, Pascal's principle states that a small force applied to a small piston creates a larger force on a larger piston, allowing for the amplification of force.