Explanation

Solids:

• Have a definite shape and volume.
• Their particles are tightly packed and vibrate in fixed positions.

Liquids:

• Have a definite volume but take the shape of their container.
• Their particles are close but can move past one another.

Gases:

• Have no definite shape or volume and expand to fill their container.
• Their particles are far apart and move freely. 

Explanation

As altitude increases, pressure decreases because there is less air above, resulting in less weight pressing down.

This causes the air to become less dense and "thinner," meaning there are fewer air molecules in a given volume. 

Pressure measures force per unit area, with SI units of pascals (1 pascal = 1 newton per square metre, 1 N/m2).

Explanation

A quantity refers to a measurable property of something.

Mass is a fundamental quantity, meaning it cannot be expressed in terms of other quantities.

It represents the amount of matter in an object. 

Explanation

 Volume is a scalar quality.

It is a physical quantity that measures the amount of three-dimensional space

Occupied by matter and is completely described by its magnitude alone, unlike vectors which also have direction. 

Explanation

Reflecting telescope: uses a concave mirror (primary) and a plane mirror (secondary).

• Concave mirror collects/focuses light.
• Plane mirror directs it to the eyepiece.
• No chromatic aberration; can be built larger than lenses.

Explanation

Helical gear, more commonly known as double helical or herringbone gears.

This design cancels out the axial thrust forces that typically put a load on the shaft. 

Explanation

Frictional force is directly proportional to the normal force, which for a horizontal surface is equal to the weight of the body.  

So, if the weight increases, the friction also increases.

- Friction ∝ Normal Force (Weight on horizontal surface)

Explanation

i. Motor and ii. Turbines are both examples of drivers.

A Gas Compressor (iii) is a piece of equipment that is driven, not a driver itself. 

Motor (Driver):

An electric motor is a common driver for a gas compressor, especially for low-to-medium power requirements

Turbine (Driver):

Both gas and steam turbines are used as drivers, especially for large, high-power industrial applications like those found in oil and gas production.

Explanation

If the area reduces, the velocity increases, and the pressure decreases. 

This is based on the principle of continuity in fluid dynamics,

This states that the mass flow rate of a fluid remains constant in a closed system.

When the area of a pipe decreases, the fluid must flow faster to maintain the same flow rate, increasing velocity.

Explanation

 In a capacitive circuit, the current leads the voltage. The phase difference between the two is 90°. 

Remember the relationship

A common mnemonic to remember the phase relationship in AC circuits is "ELI the ICE man": 

ELI: In an Electric circuit with an Load (inductor), the voltage (E) leads the current (I).

ICE: In a circuit with a Capacitor, the current (I) leads the voltage (E).