Forces & Motion
(True/False)
Weight is a force.
True
Weight = mass × gravitational field strength.
MCQ
Work is done when:
A) A force is applied, but no movement occurs
B) A force is applied and causes displacement
C) An object is lifted but returns to the same place
D) No force is applied
B) – A force is applied and causes displacement
Work = Force × Distance moved in the direction of the force. If there is no movement, no work is done.
(True/False)
Convection currents can occur in both liquids and gases.
True
Convection happens when warmer, less dense fluid rises and cooler, denser fluid sinks. This works in liquids and gases.
(MCQ)
Sound waves are:
A) Transverse
B) Longitudinal
C) Electromagnetic
D) Standing waves
B) Longitudinal
In sound waves, particles vibrate parallel to the direction of wave travel.
(MCQ)
Light travels in:
A) Straight lines
B) Curved paths
C) Circles
D) Zig-zags
A) Straight lines
Light travels in straight lines unless it is reflected or refracted.
(MCQ)
The unit of pressure is:
A) Pascal
B) Newton
C) Joule
D) Watt
A) Pascal
Pressure = Force ÷ Area = N/m² = Pa.
(True/False)
The SI unit of work is the Joule (J).
True
1 Joule is the work done when a force of 1 N moves an object 1 m in the direction of the force.
(MCQ)
Which of the following is NOT a method of heat transfer?
A) Conduction
B) Convection
C) Radiation
D) Reflection
D) Reflection
Heat is transferred by conduction (solids), convection (fluids), and radiation (through space). Reflection is about light, not heat transfer.
(True/False)
Sound can travel through a vacuum.
False
Sound needs a medium (solid, liquid, or gas). In a vacuum there are no particles, so sound cannot travel.
(True/False)
A plane mirror always produces a virtual image.
True
The image in a plane mirror cannot be projected on a screen—it is upright, same size, and virtual.
(MCQ)
A car accelerates from 0 to 20 m/s in 5 s. Acceleration = ?
A) 2 m/s²
B) 4 m/s²
C) 5 m/s²
D) 10 m/s²
B) 4 m/s²
(MCQ)
Which of the following is NOT a renewable source of energy?
A) Solar
B) Wind
C) Coal
D) Hydroelectric
C) Coal
Coal is non-renewable because it takes millions of years to form. Solar, wind, and hydro are renewable.
(MCQ)
Which state of matter expands the most when heated?
A) Solid
B) Liquid
C) Gas
D) Plasma
C) Gas
(MCQ)
The distance between two crests in a wave is called:
A) Frequency
B) Amplitude
C) Wavelength
D) Perio
C) Wavelength
Wavelength is the distance between two consecutive crests or troughs.
(True/False)
The speed of light in air is slower than in glass.
False
Light travels fastest in air (or vacuum). In glass, it slows down.
(MCQ)
The pressure at the bottom of a liquid depends on:
A) Area only
B) Depth and density
C) Temperature only
D) Volume only
B) Depth and density
P = ρgh (density × gravity × depth).
(Fill in the Blank)
The SI unit of power is the ___.
Watt (W)
Power = Work ÷ Time. Unit is Joule/second = Watt.
(Short Answer)
Why does sweating cool the body?
Because evaporation of sweat takes away heat from the skin.
The process of evaporation absorbs heat energy, cooling the body.
(True/False)
High-frequency sounds have a low pitch.
False
High frequency = high pitch. Low frequency = low pitch.
(MCQ)
Which colour of light is bent the most when passing through a prism?
A) Red
B) Blue
C) Violet
D) Green
C) Violet
Violet light has the shortest wavelength and is refracted most.
(MCQ)
A boy exerts 40 N pushing a box. The box pushes back with:
A) 0 N
B) 20 N
C) 40 N
D) 80 N
C) 40 N
Newton’s Third Law: equal and opposite reaction.
(MCQ)
A 2 kg mass is lifted 3 m. Work done against gravity = ? (Take g = 10 m/s²)
A) 6 J
B) 30 J
C) 60 J
D) 300 J
C) 60 J
Work = m × g × h = 2 × 10 × 3 = 60 J.
(Fill in the Blank)
Heat naturally flows from ___ to ___.
Hot to cold
Thermal energy always flows from a region of higher temperature to lower temperature.
(MCQ)
The loudness of sound depends on:
A) Frequency
B) Amplitude
C) Wavelength
D) Speed
B) Amplitude
A greater amplitude means more energy in the wave, which makes sound louder.
(MCQ)
The mirror used by dentists to see teeth is:
A) Plane mirror
B) Convex mirror
C) Concave mirror
D) None
C) Concave mirror
Concave mirrors magnify, making teeth look bigger for examination.