Worksheet Solutions: The Hydrosphere | Window on the Word Class 7: Solutions, Notes & Worksheets PDF Download

Q1: Multiple Choice Questions (MCQs)

(i) What percentage of Earth's surface is covered with water?
(a) 50%
(b) 71%
(c) 97%
(d) 100%
Ans: (b)
About 71% of Earth's surface is covered with water.

(ii) What makes ocean water unsuitable for drinking?
(a) High temperature
(b) Low salinity
(c) High salt content
(d) Clear appearance
Ans: (c)
Ocean water is unsuitable for drinking because it contains a large amount of salt, making it highly saline.

(iii) What are the three main processes in the water cycle?
(a) Boiling, freezing, melting
(b) Evaporation, condensation, precipitation
(c) Rain, snow, hail
(d) Drinking, bathing, swimming
Ans: (b)
The three main processes in the water cycle are evaporation, condensation, and precipitation.

(iv) What primarily causes ocean waves?
(a) The Moon's gravitational pull
(b) Earth's rotation
(c) Strong winds blowing across the ocean's surface
(d) Tides
Ans: (c)
Ocean waves are primarily caused by strong winds blowing across the ocean's surface.

(v) When do neap tides occur?
(a) During a Full Moon
(b) During a New Moon
(c) When the Moon and Sun are at right angles to each other
(d) When the Moon and Sun align
Ans: (c)
Neap tides occur when the Moon and Sun are at right angles to each other during the quarter phase.

Q2: Fill in the Blanks

(i) Oceans and seas contain about ____% of the total water in the hydrosphere.
Ans: 97%

(ii) The gravitational pull of the Moon and the Sun causes the rise and fall of ocean waters, known as ____.
Ans: Tides

(iii) Ocean currents are influenced by factors like temperature, Earth's rotation, winds, density, salinity, and the shape of the ____.
Ans: Coastlines

(iv) The process of water changing from a liquid to a gas is called ____.
Ans: Evaporation

(v) Tsunami Warning Systems provide timely alerts to coastal areas in the event of ____.
Ans: Tsunamis

Q3: Match the Column

Match the items in Column A with their corresponding descriptions in Column B.
Ans:

Q4: True/False

(i) Ocean water is low in salinity and safe to drink.
Ans: False
Ocean water is high in salinity and unsuitable for drinking.

(ii) Tides are caused by the gravitational pull of the Moon and the Sun.
Ans: True
Tides are indeed caused by the gravitational pull of the Moon and the Sun.

(iii) Ocean currents play no role in regulating global temperatures.
Ans: False
Ocean currents do play a role in regulating global temperatures.

(iv) Spring tides occur when the Moon and Sun are at right angles to each other.
Ans: False
Spring tides occur when the Moon and Sun align.

(v) Tsunami Warning Systems were implemented to prevent thunderstorms.
Ans: False
Tsunami Warning Systems were implemented to provide alerts for tsunamis, not thunderstorms.