Measurement Book Back Questions 9th Science Lesson 1
9th Science Lesson 1
1] Measurement
Book Back Questions with Answer and Do You Know Box Content
Do You Know?
The nearest star alpha centauri is about 1.34 parsec from the sun. Most of the stars visible to the unaided eye in the night sky are within 500 parsec distance from the sun.
Mass of 1 ml of water = 1 g. Mass of 1 l of water = 1kg. Mass of the other liquids vary with their density.
Problem 1: Calculate the correct reading, if the main scale reading is 8 cm, vernier coincidence is 4 and positive zero error is 0.05 cm.
Solution: Correct reading = 8 cm + (4 x 0.01 cm) – 0.05 cm = 8 + 0.04 – 0.05 = 8 – 0.01 = 7.99 cm.
Problem 2: The main scale reading is 8 cm and vernier coincidence is 4 and negative zero error is 0.02 cm. Then calculate the correct reading.
Solution: Correct reading = 8 cm + (4 x 0.01 cm) + (0.02 cm) = 8 + 0.04 + 0.02 = 8.06 cm.
The shell of an egg is 12% of its mass. A blue whale can weigh as much as 30 elephants and it is as long as 3 larger tour buses.
Problem 3: If a man has a mass 50 kg on the earth, then what is his weight?
Solution: Weight (w) = mg
Mass of a man = 50 kg
His weight = 50 x 9.8
w = 490 newton.
Choose the best answers:
1. Choose the correct one.
(a) mm < cm < m < km
(b) mm > cm > m > km
(c) km < m < cm < mm
(d) mm > m > cm > km
2. Rulers, measuring tapes and metre scales are used to measure
(a) Mass
(b) weight
(c) time
(d) length
3. 1 metric ton is equal to
(a) 100 quintals
(b) 10 quintals
(c) 1/10 quintals
(d) 1/100 quintals
4. Which among the following is not a device to measure mass?
(a) Spring balance
(b) Beam balance
(c) Physical balance
(d) Digital balance
Fill in the blanks:
1. Metre is the unit of ________________.
2. 1 kg of rice is weighed by ______________.
3. Thickness of a cricket ball is measured by _______________.
4. Radius of a thin wire is measured by _______________.
5. A physical balance measures small differences in mass up to ______________.
State true or false. If false, correct the statement:
1. The SI unit of electric current is kilogram.
2. Kilometre is one of the SI units of measurement.
3. In everyday life, we use the term weight instead of mass.
4. A physical balance is more sensitive than a beam balance.
5. One Celsius degree is an interval of 1 K and zero degree Celsius is 273.15 K.
6. With the help of vernier calliper we can have an accuracy of 0.1 mm and with screw gauge we can have an accuracy of 0.01 mm.
Match the following:
(a)
1. Length – Kelvin
2. Mass – metre
3. Time – kilogram
4. Temperature – second
(b)
1. Screw gauge – vegetables
2. Vernier calliper – coins
3. Beam balance – gold ornaments
4. Digital balance – cricket ball
Consider the statements given below and choose the correct option:
(a) Both A and R are true but R is not the correct reason.
(b) Both A and R are true and R is the correct reason.
(c) A is true but R is false.
(d) A is false but R is true.
1. Assertion (A) : The scientifically correct expression is “The mass of the bag is 10 kg”
Reason (R) : In everyday life, we use the term weight instead of mass.
2. Assertion (A) : 0oC = 273.16 K. For our convenience we take it as 273 K after rounding off the decimal.
Reason (R) : To convert a temperature on the Celsius scale we have to add 273 to the given temperature.
3. Assertion (A) : Distance between two celestial bodies is measured in terms of light year.
Reason (R) : The distance travelled by the light in one year is one light year.
Answers:
Choose the best answers:
1. mm< cm < m < km 2. Lengths 3. 10 quintals 4. Spring balance
Fill in the blanks:
1. Length 2. Beam balance 3. Vernier Caliper 4. Screw gauge 5. 1 mg
State true or false. If false, correct the statement:
1.False
Correct answer: The SI unit of electric current is Ampere
2.False
Correct answer: Metre is one of the SI units of measurement
3.True
4.True
5.False
Correct answer: One Celsius degree is an interval of 1K and zero degree Celsius is – 273.15 K
6.False
Correct answer: With the help of vernier caliper we can have an accuracy of 0.01 cm and with screw gauge we can have an accuracy of 0.01 mm
Match the following:
a)
1.Length- metre
2.Mass- kilogram
3.Time- second
4.Temperature- Kelvin
b)
1.Screw gauge- Coins
2.Vernier caliper- Cricket ball
3.Beam balance- Vegetables
4.Digital balance- Gold ornaments
Consider the statements given below and choose the correct option:
1.Both A and R are true but R is not the correct reason
2.Both A and R are true and R is the correct reason
3.Both A and R are true and R is the correct reason