Read the main scale reading.

The main scale shows markings in millimetres. The last visible mark on the main scale before the thimble is $5 \text{ mm}$. There is also a half-millimetre mark visible after the $5 \text{ mm}$ mark.
Main scale reading = $5.5 \text{ mm}$

The thimble scale shows divisions from 0 to 50. The line on the thimble scale that aligns with the main scale line is 32.
Thimble scale reading = $32 \times 0.01 \text{ mm} = 0.32 \text{ mm}$

Total reading = Main scale reading + Thimble scale reading
Total reading = $5.5 \text{ mm} + 0.32 \text{ mm} = 5.82 \text{ mm}$

The correct option is C.

For question 29:

The unit of force is the newton (N).

• A watt (W) is the unit of power.
• A joule (J) is the unit of energy or work.
• An ampere (A) is the unit of electric current.

The correct option is D.

For question 30:

Load (weight of the object), $W = 900 \text{ N}$
Height raised, $h = 1 \text{ m}$
Effort applied, $E = 300 \text{ N}$
Length of the inclined plane, $L = 4 \text{ m}$

Work output = Load $\times$ Vertical height

Work input = Effort $\times$ Distance moved along the plane

Efficiency ($\eta$) is the ratio of work output to work input, expressed as a percentage.

The correct option is D.