Free NTA Physics Question and Answers — Questions and Answers
Question 1: What is Newton's First Law of Motion?
- For every action, there is an equal and opposite reaction.
- An object in motion stays in motion unless acted upon by an external force. (Correct answer)
- The force acting on an object is equal to its mass times its acceleration.
- Energy cannot be created or destroyed, only transformed.
Correct answer: An object in motion stays in motion unless acted upon by an external force.
Newton's First Law of Motion, also known as the Law of Inertia, states that an object at rest will stay at rest, and an object in motion will stay in motion with the same speed and in the same direction, unless acted upon by an unbalanced external force. This law describes the tendency of objects to resist changes in their state of motion.
Question 2: What is the unit of electrical resistance?
- Volt
- Ampere
- Ohm (Correct answer)
- Watt
Correct answer: Ohm
The Ohm (Ω) is the standard unit of electrical resistance, named after German physicist Georg Simon Ohm. Electrical resistance is a measure of how much a material opposes the flow of electric current. A higher resistance means that more voltage is required to produce a given current.
Question 3: Which law explains why a rocket can move in space?
- Newton's First Law
- Newton's Second Law
- Newton's Third Law (Correct answer)
- The Law of Conservation of Energy
Correct answer: Newton's Third Law
Newton's Third Law states that for every action, there is an equal and opposite reaction. A rocket expels hot gases downwards (action), and in response, the gases exert an equal and opposite force upwards, propelling the rocket forward. This principle allows the rocket to accelerate even in the vacuum of space, as it doesn't need air to push against.
Question 4: What is the speed of light in a vacuum?
- 3 × 10^6 meters per second
- 3 × 10^8 meters per second (Correct answer)
- 3 × 10^10 meters per second
- 3 × 10^12 meters per second
Correct answer: 3 × 10^8 meters per second
The speed of light in a vacuum, denoted by 'c', is a fundamental physical constant. Its universally accepted value is approximately 299,792,458 meters per second, which is commonly rounded to 3 × 10^8 meters per second. This speed represents the absolute upper limit for the speed at which all conventional matter and information can travel.
Question 5: What is the principle of conservation of energy?
- Energy is always increasing in a closed system.
- Energy can neither be created nor destroyed, only transformed. (Correct answer)
- Energy is only conserved in isolated systems.
- Energy can be created by converting mass.
Correct answer: Energy can neither be created nor destroyed, only transformed.
The principle of conservation of energy, also known as the First Law of Thermodynamics, states that energy cannot be created or destroyed within a closed system. Instead, it can only be transformed from one form to another, such as from potential energy to kinetic energy or chemical energy to heat. The total amount of energy in the universe remains constant, only changing its manifestation.
Free NTA Physics Question and Answers
What is Newton's First Law of Motion?