Match List-I with List-II.
| List-I | List-II | ||
|---|---|---|---|
| (Instrument) | (Use) | ||
| (A) | Lactometer | (I) | Detects the presence of an electric charge |
| (B) | Electroscope | (II) | Used to detect objects under water |
| (C) | Manometer | (III) | Measures the relative density of milk to determine its purity |
| (D) | Sonar | (IV) | Measures the pressure of gases |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A-III, B-I, C-IV, D-II
Each instrument is named after what it measures or detects.
(A) Lactometer — this matches (III) Measures the relative density of milk to determine its purity. It floats in milk; water added to milk lowers the density, so the lactometer sinks deeper.
(B) Electroscope — this matches (I) Detects the presence of an electric charge. When a charged body touches its metal cap, its two thin leaves get the same charge and spread apart.
(C) Manometer — this matches (IV) Measures the pressure of gases. The difference in the levels of liquid in its U-tube shows the pressure of the gas.
(D) Sonar — this matches (II) Used to detect objects under water. It sends out ultrasonic waves and times their echo from submarines, shoals of fish or the sea bed.