PHYSICS QUESTIONS AND ANSWERS A+ ,100+
What is Newton's First Law of Motion, and what does it state about the behavior of objects at rest and in
motion?
An object at rest remains at rest, and an object in motion remains in motion with the same speed and
direction unless acted upon by an unbalanced external force.
What is the formula for calculating the force exerted by an object and the principle it follows?
Force (F) is calculated using the formula F=maF = ma, where mm is mass and aa is acceleration. It follows
Newton's Second Law of Motion.
Explain the concept of gravitational potential energy and provide its equation.
Gravitational potential energy is the energy an object possesses due to its position in a gravitational field.
The equation is U=mghU = mgh, where mm is mass, gg is gravitational acceleration, and hh is height
above a reference point.
What is the difference between speed and velocity in physics?
Speed is a scalar quantity that measures the rate of motion, while velocity is a vector quantity that
includes both the magnitude and direction of motion.
Describe the phenomenon of refraction and state Snell’s Law.
Refraction is the bending of light as it passes from one medium to another with a different refractive
index. Snell's Law is given by n1sinθ1=n2sinθ2n_1 \sin \theta_1 = n_2 \sin \theta_2, where n1n_1
and n2n_2 are the refractive indices, and θ1\theta_1 and θ2\theta_2 are the angles of incidence and
refraction, respectively.
What is the relationship between work, energy, and power? Define each term.
Work is the transfer of energy when a force is applied over a distance. Energy is the capacity to perform
work. Power is the rate at which work is done or energy is transferred, given by P=WtP = \frac{W}{t},
where WW is work and tt is time.
Explain the law of conservation of energy and its implications.
The law of conservation of energy states that energy cannot be created or destroyed; it can only be
transformed from one form to another. The total energy in an isolated system remains constant.
How do we calculate the centripetal force acting on an object moving in a circular path?
The centripetal force FcF_c is calculated using the formula Fc=mv2rF_c = \frac{mv^2}{r}, where mm is
mass, vv is velocity, and rr is the radius of the circular path.
What is the photoelectric effect, and how does it demonstrate the particle nature of light?
The photoelectric effect is the emission of electrons from a material's surface when light of sufficient
frequency shines on it. It demonstrates the particle nature of light because the effect depends on light
being composed of photons with quantized energy.
What is the difference between longitudinal and transverse waves?
Longitudinal waves have particle oscillations parallel to the direction of wave propagation, while
transverse waves have particle oscillations perpendicular to the direction of wave propagation.
, Define and explain Hooke’s Law for elastic materials.
Hooke’s Law states that the force required to extend or compress a spring is directly proportional to the
displacement, given by F=−kxF = -kx, where kk is the spring constant and xx is the displacement from
equilibrium.
What is the Doppler effect, and how does it relate to the observed frequency of waves?
The Doppler effect is the change in the observed frequency of a wave due to the relative motion
between the source and the observer. The frequency increases if the source and observer are moving
closer and decreases if they are moving apart.
How is electric current defined, and what is its relation to charge?
Electric current is the rate of flow of electric charge, given by I=QtI = \frac{Q}{t}, where II is current, QQ is
charge, and tt is time.
What is the principle of superposition in wave mechanics?
The principle of superposition states that when two or more waves overlap, the resulting displacement
at any point is equal to the sum of the displacements of the individual waves at that point.
Explain the concept of torque and its formula.
Torque is the rotational equivalent of force and measures the tendency of a force to rotate an object
around an axis. The formula is τ=rFsinθ\tau = rF \sin \theta, where τ\tau is torque, rr is the lever arm,
FF is the force, and θ\theta is the angle between the force and lever arm.
What is the net force acting on an object of mass 5 kg accelerating at 3 m/s²?
15 N
Explain how Newton’s third law applies to a rocket launch.
During a rocket launch, the engines exert a downward force by expelling exhaust gases, while an equal
and opposite upward force is exerted on the rocket, propelling it upward.
A car traveling at 20 m/s comes to a stop in 5 seconds. What is the car’s deceleration?
-4 m/s²
If a 10 kg object experiences a gravitational force of 98 N, what is the value of the gravitational field
strength?
9.8 N/kg
Describe the energy transformations that occur when a pendulum swings.
As the pendulum swings, gravitational potential energy is converted into kinetic energy and vice versa. At
the highest points, potential energy is maximum, and at the lowest point, kinetic energy is maximum.
What is the work done when a force of 50 N is applied to push an object 3 meters in the direction of the
force?
150 J
Why does a ball thrown upwards slow down as it rises?
The ball slows down due to the force of gravity acting in the opposite direction to its motion, causing a
deceleration.
What is Newton's First Law of Motion, and what does it state about the behavior of objects at rest and in
motion?
An object at rest remains at rest, and an object in motion remains in motion with the same speed and
direction unless acted upon by an unbalanced external force.
What is the formula for calculating the force exerted by an object and the principle it follows?
Force (F) is calculated using the formula F=maF = ma, where mm is mass and aa is acceleration. It follows
Newton's Second Law of Motion.
Explain the concept of gravitational potential energy and provide its equation.
Gravitational potential energy is the energy an object possesses due to its position in a gravitational field.
The equation is U=mghU = mgh, where mm is mass, gg is gravitational acceleration, and hh is height
above a reference point.
What is the difference between speed and velocity in physics?
Speed is a scalar quantity that measures the rate of motion, while velocity is a vector quantity that
includes both the magnitude and direction of motion.
Describe the phenomenon of refraction and state Snell’s Law.
Refraction is the bending of light as it passes from one medium to another with a different refractive
index. Snell's Law is given by n1sinθ1=n2sinθ2n_1 \sin \theta_1 = n_2 \sin \theta_2, where n1n_1
and n2n_2 are the refractive indices, and θ1\theta_1 and θ2\theta_2 are the angles of incidence and
refraction, respectively.
What is the relationship between work, energy, and power? Define each term.
Work is the transfer of energy when a force is applied over a distance. Energy is the capacity to perform
work. Power is the rate at which work is done or energy is transferred, given by P=WtP = \frac{W}{t},
where WW is work and tt is time.
Explain the law of conservation of energy and its implications.
The law of conservation of energy states that energy cannot be created or destroyed; it can only be
transformed from one form to another. The total energy in an isolated system remains constant.
How do we calculate the centripetal force acting on an object moving in a circular path?
The centripetal force FcF_c is calculated using the formula Fc=mv2rF_c = \frac{mv^2}{r}, where mm is
mass, vv is velocity, and rr is the radius of the circular path.
What is the photoelectric effect, and how does it demonstrate the particle nature of light?
The photoelectric effect is the emission of electrons from a material's surface when light of sufficient
frequency shines on it. It demonstrates the particle nature of light because the effect depends on light
being composed of photons with quantized energy.
What is the difference between longitudinal and transverse waves?
Longitudinal waves have particle oscillations parallel to the direction of wave propagation, while
transverse waves have particle oscillations perpendicular to the direction of wave propagation.
, Define and explain Hooke’s Law for elastic materials.
Hooke’s Law states that the force required to extend or compress a spring is directly proportional to the
displacement, given by F=−kxF = -kx, where kk is the spring constant and xx is the displacement from
equilibrium.
What is the Doppler effect, and how does it relate to the observed frequency of waves?
The Doppler effect is the change in the observed frequency of a wave due to the relative motion
between the source and the observer. The frequency increases if the source and observer are moving
closer and decreases if they are moving apart.
How is electric current defined, and what is its relation to charge?
Electric current is the rate of flow of electric charge, given by I=QtI = \frac{Q}{t}, where II is current, QQ is
charge, and tt is time.
What is the principle of superposition in wave mechanics?
The principle of superposition states that when two or more waves overlap, the resulting displacement
at any point is equal to the sum of the displacements of the individual waves at that point.
Explain the concept of torque and its formula.
Torque is the rotational equivalent of force and measures the tendency of a force to rotate an object
around an axis. The formula is τ=rFsinθ\tau = rF \sin \theta, where τ\tau is torque, rr is the lever arm,
FF is the force, and θ\theta is the angle between the force and lever arm.
What is the net force acting on an object of mass 5 kg accelerating at 3 m/s²?
15 N
Explain how Newton’s third law applies to a rocket launch.
During a rocket launch, the engines exert a downward force by expelling exhaust gases, while an equal
and opposite upward force is exerted on the rocket, propelling it upward.
A car traveling at 20 m/s comes to a stop in 5 seconds. What is the car’s deceleration?
-4 m/s²
If a 10 kg object experiences a gravitational force of 98 N, what is the value of the gravitational field
strength?
9.8 N/kg
Describe the energy transformations that occur when a pendulum swings.
As the pendulum swings, gravitational potential energy is converted into kinetic energy and vice versa. At
the highest points, potential energy is maximum, and at the lowest point, kinetic energy is maximum.
What is the work done when a force of 50 N is applied to push an object 3 meters in the direction of the
force?
150 J
Why does a ball thrown upwards slow down as it rises?
The ball slows down due to the force of gravity acting in the opposite direction to its motion, causing a
deceleration.
