1. Tick (✔) the correct option:
(a) Wind vane is used to find out
(i) Pressure
(ii) Temperature
(iii) Direction ✔
(iv) Speed
(b) The unit of pressure is
(i) Cm
(ii) Mb (Millibar) ✔
(iii) Degree Celsius
(iv) Percent
(c) Relative humidity is measured by
(i) Wet and Dry Bulb Thermometer ✔
(ii) Rain gauge
(iii) Thermometer
(iv) Stevenson Screen
(d) Wind speed is measured in
(i) km per hour
(ii) miles per minute
(iii) knots
(iv) metres per second ✔
(e) Science that deals with the study of weather.
(i) anthropology
(ii) zoology
(iii) meteorology ✔
(iv) seismology
(f) This is not an element of weather and climate.
(i) temperature
(ii) sunshine
(iii) humidity
(iv) isotherm ✔ (It’s a line on a map, not an element)
(g) What instrument is used to measure temperature?
(i) barometer
(ii) thermometer ✔
(iii) hygrometer
(iv) weather cock
(h) Atmospheric pressure decreases with increase in ______.
(i) latitude
(ii) altitude ✔
(iii) distance from the sea
(iv) wind speed
(i) The actual amount of water vapour present in the atmosphere is
(i) actual vapour
(ii) relative humidity
(iii) absolute humidity ✔
(Note: Option (iv) “humidity” is too general, but absolute humidity is the correct specific term for the actual amount.)
(j) The atmospheric pressure at the sea level is
(i) 1013 gm/sq cm
(ii) 4301 gm/sq cm
(iii) 1013.25 mb (approx. 1034 gm/sq cm is close for the force) ✔
(iv) 4301 km/sq cm
*(Closest standard value is 1013.25 mb, which is roughly 1034 gm/cm²)*
(k) Temperature at which air gets saturated.
(i) frost point
(ii) hail point
(iii) sleet point
(iv) dew point ✔
(l) Lines on a weather map joining places having equal pressure are called
(i) Isohytes
(ii) isohales
(iii) isobars ✔
(iv) isotherm
(m) Scale measuring the force of winds at sea
(i) primary scale
(ii) verbal scale
(iii) Beaufort scale ✔
(iv) statement scale
(n) Winds are attracted towards
(i) low pressure region ✔
(ii) high pressure region
(iii) low temperature region
(iv) high temperature region
(o) Lines on a weather map joining places having equal amount of precipitation
(i) isobar
(ii) isohyet ✔
(iii) isohale
(iv) isotherm
(p) Provides imagery and data on space weather
(i) GOES (Geostationary Operational Environmental Satellite) ✔
(ii) COMES
(iii) STOPS
(iv) MOVES
(q) In Celsius the freezing point of water is
(i) 212°
(ii) 100°
(iii) 0° ✔
(iv) 32
2. Fill in the blanks:
(a) ______ is a place where weather conditions are recorded with the help of instruments.
Answer: A Meteorological Station or Weather Station
(b) ______ is used to measure rainfall.
Answer: A Rain Gauge
(c) ______ thermometer can record the highest and the lowest temperature of a given period.
Answer: A Six’s Thermometer or Maximum-Minimum Thermometer
(d) Horizontal movement of air near the surface of the earth is called ______.
Answer: Wind
3. Distinguish between the following:
(i) Climate and Weather
| Climate | Weather |
| The average atmospheric conditions of a place over a long period (usually 30-35 years). | The day-to-day state of the atmosphere at a place. |
| It describes the long-term pattern. | It describes the short-term condition (hours/days). |
| It is permanent and remains more or less the same year after year. | It is temporary and changes frequently. |
| Example: The climate of Rajasthan is hot and dry. | Example: The weather today in Delhi is sunny and warm. |
(ii) Absolute and Relative Humidity
| Absolute Humidity | Relative Humidity |
| The actual mass or weight of water vapour present in a unit volume of air (grams per cubic meter). | The ratio of the actual amount of water vapour in the air to the maximum amount the air can hold at that temperature. |
| It is expressed in grams per cubic meter (g/m³). | It is expressed as a percentage (%). |
| It is not affected by changes in temperature. | It changes with temperature (even if the moisture content stays the same). |
(iii) Diurnal range of temperature and Annual range of temperature
| Diurnal Range of Temperature | Annual Range of Temperature |
| The difference between the maximum and minimum temperature of a single day. | The difference between the average temperatures of the hottest and coldest months of the year. |
| It is calculated over a 24-hour period. | It is calculated over a 12-month period. |
| Example: If the max temp is 30°C and the min is 20°C, the diurnal range is 10°C. | Example: If the hottest month’s avg. temp is 35°C and the coldest is 15°C, the annual range is 20°C. |
4. Answer the following questions in brief:
(a) Name the elements of weather.
Answer: The main elements of weather are temperature, atmospheric pressure, wind (including its speed and direction), humidity, cloudiness, and precipitation (such as rain, snow, or hail). These components work together to define the short-term atmospheric conditions at a specific place and time.
(b) Name the instruments used for the following:
(i) Atmospheric pressure
Answer: Barometer
(ii) Wind speed
Answer: Anemometer
(iii) Rainfall
Answer: Rain Gauge
(iv) Humidity
Answer: Hygrometer (A Wet and Dry Bulb Thermometer, or Psychrometer, is a common type)
(v) Temperature
Answer: Thermometer
(c) State the use of Wet and Dry Bulb Thermometer.
Answer: A Wet and Dry Bulb Thermometer, also known as a Psychrometer, is used to measure the relative humidity of the air. It consists of two thermometers. The “dry bulb” measures the air temperature, while the “wet bulb” has its bulb covered with a moist cloth. Water evaporating from this cloth cools the wet bulb. The difference between the two thermometer readings is used with a special chart to calculate the relative humidity.
(d) What is the purpose of the meteorological station?
Answer: The purpose of a meteorological station is to systematically observe, measure, and record the various elements of weather using specialized instruments. It serves as a central point for collecting accurate data on temperature, pressure, humidity, wind, and rainfall. This data is crucial for creating weather forecasts, studying climate patterns, and providing essential information for agriculture, aviation, shipping, and disaster management.
(e) What is the purpose of an anemometer?
Answer: The purpose of an anemometer is to measure the speed of the wind. It typically consists of three or four cups mounted on arms that rotate horizontally in the wind. The faster the wind blows, the faster the cups spin. This rotation speed is converted into an electrical signal or a mechanical reading that indicates the wind speed in units like kilometers per hour or meters per second, which is vital for weather forecasting and safety warnings.
(f) What are weather maps used for?
Answer: Weather maps are used to visually represent and summarize current weather conditions and forecast future weather patterns over a large geographical area. They display data collected from various weather stations using symbols, isobars (lines of equal pressure), isotherms (lines of equal temperature), and color codes. Meteorologists use these maps to analyze weather systems like high and low-pressure areas, fronts, and storm paths, enabling them to issue accurate forecasts and severe weather warnings to the public.