# Measurement of Mass and Time Class-6th Goyal Brothers Physics Solutions

Measurement of Mass and Time Class-6th Goyal Brothers Physics Solutions Chapter-2, Unit 2. We Provide Step by Step Answers of Objective, True False , Fill in the blanks, Match the following , Study Questions of Chapter- 2 , Physical quantities and measurements, Unit-2 (Measurement of Mass and Time). Visit official Website  for detail information about ICSE Board Class-6.

## Measurement of Mass and Time Class-6th

Goyal Brothers Physics Solutions Chapter-2 (Unit 2)

 Board ICSE Class 6th Subject Physics Book Name Goyal Brothers Theme-2 Physical quantities and measurements Unit-2 Measurement of Mass and Time Topic Solution of exercise questions Session 2023-24

### OBJECTIVE TYPE QUESTIONS

Physics Solutions Chapter-2, unit-2

#### A. Fill in the blanks :

1. _Mass_is the quantity of matter in a given object.
2. The SI unit of mass is _Kilogram_.
3. _Time_ is the interval between two events.
4. The SI unit of time is _second_.
5. 1/1440 part of a mean solar day is called _minute_.

#### B. Write ‘True’ or ‘False’ for the following statements :

1. Kilometre is a multiple of milligram. [F]
2. SI unit of time is mean solar day. [F]
3. One millennium constitutes 10 centimetres. [F]
4. The minute is proper unit to record 100 m race. [T]
5. A physical balance is used to find mass of vegetables. [T]

#### C. Statement given below are incorrect. write the correct correct statement:

1. SI unit of time is a solar day.

Correct Statement: SI unit of time is a second.

2. A pendulum swinging freely (length 100 cm) completes one oscillation in one second.

Correct Statement: A pendulum swinging freely (length 100 cm) completes one oscillation in two second.

3. In international markets the food grains are sold in kilogram.

Correct Statement: In international markets the food grains are sold in tonne.

4. One milligram is 1/100 part of one gram.

Correct Statement: One milligram is 1/1000 part of one gram.

5. Twenty four hour clock is used in government offices.

Correct Statement: Twenty four hour clock is used in railway offices.

#### 1. The SI unit of mass is:

(a) metric tonne

(b) quintal

(c) kilogram

(d) gram

Ans: (c) kilogram

#### 2. The correct unit for exporting food grains to other countries is :

(a) quintal

(b) metric-tonne

(c) kilometre

(d) gram

Ans: (b) metric-tonne

(a) 200 cm

(b) 50 cm

(c) 75 cm

(d) 100 cm

Ans: (d) 100 cm

(a) 1/86400

(b) 1/68400

(c) 1/48600

(d) 1/84600

Ans: (a) 1/86400

#### 5. A to and fro motion of swinging pendulum about its mean position.

Column A Column B

### STUDY QUESTIONS

#### Question 1. What do you understand by the term mass? State its SI unit.

Answer: The mass of an object is the amount of matter contained in it. The si unit of mass is Kilogram (Kg).

#### Question 2. Name two multiples and two submultiples of SI unit of mass.

Answer: Two Multiple units of SI unit of mass are Ton and Quintal used for measuring heavy weights. Two Sub-multiple  units of SI unit of mass are Gram and Milligram.

#### Question 3. What kind of balance is used for finding the mass of (a) gold ornament (b) vegetables ?

Answer: (a) For measuring the mass of costly substances such as gold, silver and diamonds, we use physical balance.

(b) Balance used for finding the mass of vegetable is beam balance.

#### Question 4. What do you understand by the term time? State its SI unit ?

Answer: The duration between any two events is called time. The SI unit of time is second (s).

#### Question 5. (a) How many centuries make one millennium?

Answer: 10 centuries make one millennium

#### (c) How many years make one millennium?

Answer: 100 calendar year  make one millennium.

#### Question 6. (a) What do you understand by the term mean solar day.

Answer: A solar day is the time it takes for the Earth to rotate about its axis so that the Sun appears in the same position in the sky,

#### (b) How many hours are there in one mean solar day?

Answer: There are 24 hours in one mean solar day.

#### (c) How many minutes are there in one mean solar day?

Answer: There are 1440 minutes in one mean solar day.

#### (d) How many seconds are there in one mean solar day?

Answer: There are 86400 seconds in one mean solar day.

#### Question 7. Define the following terms:

(a) Simple pendulum: A simple pendulum consists of a bob suspended at the end of a thread that is so light as to be considered massless. The period of such a device can be made longer by increasing its length, as measured from the point of suspension to the middle of the bob.

(b) Oscillation: It is the to and fro motion of the bob starts from one end and comes back to the same position, it is known as one oscillation of a pendulum

(c) length of pendulum: The length between the point of suspension to the center of the bob is called the Length of the Pendulum.

(d) Time period: The time taken for one complete oscillation to occur is called the Time Period.

#### (a) The time period of a second’s pendulum is 2 s. What is the length of pendulum?

Answer: Using the formula, L = (T/ 2π)²*g , we can determine that the length of a simple pendulum with a time period of 2 seconds. Hence, the length of the second’s pendulum is 99.3 cm.

#### (a) What is 24 hour clock ?

Answer: Under the 24-hour clock system, the day begins at midnight, 00:00, and the last minute of the day begins at 23:59 and ends at 24:00, which is identical to 00:00 of the following day. 12:00 can only be noon (midday).

#### (b) Name two organisations which use 24 hour clock.

Answer:  Two organisations which use 24 hour clocks are :-

• In Airport timetable.
• In railways time table.

#### (c) The time on 24 hour clock is :

• 08 h 37 min
• 23 h 48 min. Explain the time on 12 hours clock

Answer:  08 h – 37 min = 08:37 A.M

23 h – 48 min = (23:48 – 12:00)h = 11 h 48 min = 11:48 P.M

#### (a) What is 12 hour clock?

Answer:  The 12 Hours running from Midnight to Noon (the AM hours), and. The other 12 Hours running from Noon to Midnight (the PM hours).

#### (b) What are indications of a.m. and p.m. on 12 hour clock?

Answer: The meaning of AM and PM is ‘Ante Meridiem’ and ‘Post Meridiem’, which means before noon or midday. We associate P.M. with the afternoon and evening. P.M. is an abbreviated term for ‘Post Meridiem,’ which implies afternoon or after midday. In a 12-hour clock, these are used as time indications centered around noon

#### (c) The time on 12 hour clock is:

• 3 h 30 min p.m.
• 9 h 40 min a.m.

convert the time on 24 h clock.

Answer:   3 h 30 min p.m. is written as 15 : 30 hours in the 24-hour clock.

9 h 40 min a.m  is written as 9;40.

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