(a) The height difference, h, is the difference between the two mercury levels: \(h = 242 \text{ mm} - 82 \text{ mm} = \textbf{160 mm}\).

(b) The gas supply's pressure is the sum of the atmospheric pressure and the difference in mercury levels: \(760 \text{ mm Hg} + 160 \text{ mm Hg} = \textbf{920 mm Hg}\).

The stopwatch shows a time of 7 minutes and 20 seconds, which translates to \( (7 \text{ min} \times 60 \text{ s/min}) + 20 \text{ s} = \textbf{440 s}\).

(a) The volume of water is read directly from the measuring cylinder: \(\textbf{15 cm}^3\).

(b) The volume of the 20 water drops is the difference between the new volume and the initial volume: \(25 \text{ cm}^3 - 15 \text{ cm}^3 = 10 \text{ cm}^3\). The average volume of one drop is this volume divided by the number of drops: \(10 \text{ cm}^3 / 20 \text{ drops} = \textbf{0.5 cm}^3\textbf{/drop}\).

The volume is read directly from the measuring cylinder as \(\textbf{45 cm}^3\).

The contact area is calculated by multiplying the length and width of the block: \(12.0 \text{ cm} \times 2.0 \text{ cm} = \textbf{24.0 cm}^2\).

The average thickness of a single sheet is found by dividing the total thickness of the sheets by the number of sheets: \(29 \text{ mm} / 270 \text{ sheets} = \textbf{0.107 mm/sheet}\).

(a) Although the source doesn't specify the equipment, a measuring tape is commonly used to measure distances like 25 m.

(b) The total distance is twice the one-way distance: \(2 \times 25 \text{ m} = \textbf{50 m}\).

(a) The stopwatch displays a time of 3 minutes and 46.50 seconds, which is equal to \((3 \text{ min} \times 60 \text{ s/min}) + 46.50 \text{ s} = \textbf{226.50 s}\).

(b) Dividing the total time by the number of drops provides the average time interval between drops: \(226.50 \text{ s} / 200 \text{ drops} = \textbf{1.13 s/drop}\).

The average volume of a drop is found by dividing the total volume collected by the number of drops: \(60 \text{ cm}^3 / 200 \text{ drops} = \textbf{0.3 cm}^3\textbf{/drop}\).

While the source doesn't mention a specific term, a graduated cylinder or measuring cylinder is typically used for accurate volume measurement.