QUESTION BANK

CLASS VII SCIENCE

CHAPTER VIII: MEASUREMENT OF TIME AND MOTION

Direct Questions Assertion / Reason Correct / Incorrect HOTS Challenging

DIRECT QUESTIONS

The most well-known periodic motion used for the measurement of time is that of:

A. A car

B. A simple pendulum

C. A falling stone

D. A moving train

Answer: B. A simple pendulum

The time taken by a pendulum to complete one oscillation is called its:

A. Frequency

B. Amplitude

C. Time period

D. Speed

Answer: C. Time period

The basic unit of time is:

A. Minute

B. Hour

C. Second

D. Day

Answer: C. Second

Speed is defined as:

A. Distance × Time

B. Distance / Time

C. Time / Distance

D. Distance + Time

Answer: B. Distance / Time

Which of the following is the basic unit of speed?

A. km/min

B. m/min

C. km/h

D. m/s

Answer: D. m/s

A motion that repeats itself after a fixed interval of time is called:

A. Linear motion

B. Periodic motion

C. Random motion

D. Circular motion

Answer: B. Periodic motion

The odometer of a vehicle measures:

A. Speed

B. Time

C. Distance

D. Acceleration

Answer: C. Distance

The speedometer of a vehicle measures speed in:

A. m/s

B. m/min

C. km/h

D. km/s

Answer: C. km/h

If an object moves along a straight line with a constant speed, its motion is called:

A. Non-uniform motion

B. Uniform motion

C. Periodic motion

D. Oscillatory motion

Answer: B. Uniform motion

A simple pendulum consists of a small metallic ball called a:

A. Knot

B. Bob

C. Hook

D. Rigid support

Answer: B. Bob

In a distance-time graph, a straight line inclined to the time-axis indicates:

A. The object is at rest

B. Uniform speed

C. Non-uniform speed

D. Increasing speed

Answer: B. Uniform speed

Which of the following cannot be used for the measurement of time?

A. A leaking tap

B. Simple pendulum

C. Shadow of an object during the day

D. A blinking eye

Answer: D. A blinking eye (It is not periodic/regular)

Ancient time-measuring devices included:

A. Sundials

B. Water clocks

C. Sand clocks

D. All of the above

Answer: D. All of the above

The distance-time graph for the motion of an object moving with a constant speed is a:

A. Curved line

B. Straight line

C. Circle

D. Zig-zag line

Answer: B. Straight line

If the speed of an object moving along a straight line keeps changing, its motion is:

A. Uniform

B. Non-uniform

C. Periodic

D. Stationary

Answer: B. Non-uniform

The metallic ball of a pendulum is suspended by a:

A. Thick rod

B. Taut string/thread

C. Rubber band

D. Spring

Answer: B. Taut string/thread

Which of the following is the correct relation?

A. Speed = Distance × Time

B. Speed = Distance / Time

C. Speed = Time / Distance

D. Speed = 1 / (Distance × Time)

Answer: B. Speed = Distance / Time

A car covers 20 km in 15 minutes. Its speed is:

A. 20 km/h

B. 80 km/h

C. 60 km/h

D. 40 km/h

Answer: B. 80 km/h (Speed = 20 / 0.25h)

The time period of a simple pendulum depends on its:

A. Mass of the bob

B. Length of the string

C. Amplitude of oscillation

D. Material of the bob

Answer: B. Length of the string

Quartz clocks are more ________ than pendulum clocks.

A. Expensive

B. Accurate

C. Heavy

D. Traditional

Answer: B. Accurate

One microsecond is:

A. One-millionth of a second

B. One-thousandth of a second

C. One-billionth of a second

D. Ten seconds

Answer: A. One-millionth of a second

The symbols of all units are written in:

A. Plural

B. Singular

C. Capital letters only

D. Bold letters only

Answer: B. Singular (e.g., 50 km, not 50 kms)

If a distance-time graph is a horizontal line parallel to the time axis, the object is:

A. Moving with constant speed

B. At rest

C. Moving with increasing speed

D. Moving in a circle

Answer: B. At rest

The distance covered by an object in unit time is its:

A. Acceleration

B. Speed

C. Velocity

D. Frequency

Answer: B. Speed

How many seconds are there in one hour?

A. 60

B. 360

C. 3600

D. 36000

Answer: C. 3600

A pendulum clock becomes slow in summer because:

A. The bob becomes heavier

B. The length of the string increases due to heat

C. The air becomes thicker

D. The friction increases

Answer: B. The length of the string increases due to heat

The motion of a swing is an example of:

A. Periodic motion

B. Circular motion

C. Linear motion

D. Random motion

Answer: A. Periodic motion

Which scientist was the first to realize that a pendulum of a given length always takes the same time to complete one oscillation?

A. Isaac Newton

B. Galileo Galilei

C. Albert Einstein

D. Thomas Edison

Answer: B. Galileo Galilei

The fastness or slowness of an object is determined by its:

A. Size

B. Speed

C. Color

D. Weight

Answer: B. Speed

A bus travels 54 km in 90 minutes. The speed of the bus is:

A. 0.6 m/s

B. 10 m/s

C. 54 m/s

D. 36 m/s

Answer: B. 10 m/s (54000m / 5400s)

ASSERTION AND REASON

A. Both A and R are true and R is the correct explanation of A.

B. Both A and R are true but R is not the correct explanation of A.

C. A is true but R is false.

D. A is false but R is true.

Assertion (A): The motion of a simple pendulum is periodic.

Reason (R): It repeats its motion after a regular interval of time.

Answer: A. Both A and R are true and R is the correct explanation of A.

Assertion (A): A speedometer measures the distance traveled by a vehicle.

Reason (R): Odometer is used to measure the speed of a vehicle.

Answer: D. A is false but R is true (Actually both are false, but in standard MCQ logic, if A is false, D is chosen).

Assertion (A): Speed of a vehicle is usually expressed in km/h.

Reason (R): The SI unit of speed is m/s.

Answer: B. Both A and R are true but R is not the correct explanation of A.

Assertion (A): A distance-time graph for non-uniform motion is a straight line.

Reason (R): In non-uniform motion, the object covers unequal distances in equal intervals of time.

Answer: D. A is false but R is true.

Assertion (A): The time period of a pendulum remains constant even if the length of the string is changed.

Reason (R): Galileo discovered the principle of the pendulum.

Answer: D. A is false but R is true.

CORRECT / INCORRECT STATEMENTS

Which of the following statements is INCORRECT?

A. The basic unit of time is second.

B. Every object moves with a constant speed.

C. Distance between two cities is measured in kilometers.

D. The time period of a given pendulum is constant.

Answer: B. Every object moves with a constant speed.

Identify the CORRECT statement:

A. A car moving with a constant speed covers equal distances in equal intervals of time.

B. Speedometer measures the average speed of the journey.

C. A sundial can be used to measure time at night.

D. The bob of a pendulum must be made of plastic only.

Answer: A. A car moving with a constant speed covers equal distances in equal intervals of time.

Which of the following about graphs is CORRECT?

A. The independent variable is generally plotted on the Y-axis.

B. A distance-time graph helps in finding the speed of an object.

C. A curved line in a distance-time graph represents uniform motion.

D. Time is always plotted on the Y-axis.

Answer: B. A distance-time graph helps in finding the speed of an object.

Find the INCORRECT statement:

A. 1 hour = 60 minutes.

B. 1 minute = 60 seconds.

C. The symbol for second is 'sec'.

D. All units are written in singular form.

Answer: C. The symbol for second is 'sec' (The correct symbol is 's').

HOTS (HIGHER ORDER THINKING SKILLS)

A car moves with a speed of 40 km/h for 15 minutes and then with a speed of 60 km/h for the next 15 minutes. The total distance covered by the car is:

A. 100 km

B. 25 km

C. 15 km

D. 10 km

Answer: B. 25 km (Distance 1 = 10km, Distance 2 = 15km)

Why can't we use our pulse rate as a standard unit for measuring time?

A. It is too fast.

B. It is not constant and varies with physical activity or emotions.

C. It is difficult to count.

D. It only works for humans.

Answer: B. It is not constant and varies with physical activity or emotions.

If the distance-time graph of two cars A and B are straight lines, and the slope of A is steeper than B, what does it conclude?

A. Car B is faster than car A.

B. Car A is faster than car B.

C. Both have the same speed.

D. Both cars are at rest.

Answer: B. Car A is faster than car B.

How does the time period of a pendulum change if we increase the length of its string?

A. It decreases.

B. It increases.

C. It remains the same.

D. It becomes zero.

Answer: B. It increases.

A train moves at a speed of 120 km/h. How much distance will it cover in 20 minutes?

A. 40 km

B. 60 km

C. 20 km

D. 240 km

Answer: A. 40 km (120 km/h × 1/3 h)

CHALLENGING QUESTIONS

The distance between two stations is 240 km. A train takes 4 hours to cover this distance. Its speed in m/s is:

A. 60 m/s

B. 16.6 m/s

C. 20 m/s

D. 10 m/s

Answer: B. 16.6 m/s (60 km/h × 5/18)

Which of the following distance-time graphs shows a truck moving with a speed which is not constant?

A. A straight line starting from origin.

B. A curved line.

C. A straight line parallel to time axis.

D. A straight line parallel to distance axis.

Answer: B. A curved line.

Two clocks A and B are used to measure a time interval. Clock A has a second hand, and clock B only has a minute hand. Which clock will provide a more precise measurement?

A. Clock A

B. Clock B

C. Both are equally precise

D. Neither is precise

Answer: A. Clock A

A spaceship travels 36,000 km in one hour. Its speed in km/s is:

A. 10 km/s

B. 100 km/s

C. 36 km/s

D. 600 km/s

Answer: A. 10 km/s (36000 / 3600)

If a pendulum takes 32 seconds to complete 20 oscillations, what is its time period?

A. 1.6 s

B. 0.625 s

C. 32 s

D. 20 s

Answer: A. 1.6 s (32 / 20)