All Exams  >   Grade 9  >   Physics  >   All Questions

All questions of Measurement for Grade 9 Exam

Which is the most accurate atomic clock?
  • a)
    Carbon-12 clock
  • b)
    Carbon atom clock
  • c)
    caesium atom clock
  • d)
    Stop clock
Correct answer is option 'C'. Can you explain this answer?

Nandini Patel answered
According to the most accurate caesium atomic clock in the world, 1 second is the time that elapses during 9,192,631,770 cycles of the radiation produced by the transition between two levels of the caesium 133 atom.

Can you explain the answer of this question below:
The method used to measure the distance of a planet from the earth is
  • A:
    Parallax method
  • B:
    Archimedes’ method
  • C:
    Newton’s method
  • D:
    Galileo’s method
The answer is a.

Yash Ghoshal answered
The astronomers mainly use parallax method to find distances to objects like other planets. To calculate the distance to a star or to a planet, astronomers observe it from different places along Earth's orbit around the Sun.

Can you explain the answer of this question below:

 Which of the following is caused by careless handling?

  • A:

    Systematic error

  • B:

    Gross error

  • C:

    Random error

  • D:

    None of the mentioned

The answer is b.

Nandini Iyer answered
Gross errors are mostly due to lack of knowledge, judgment and care on the part of experiment. That is Gross error is caused by careless handling.

 Which of the following is caused by careless handling?
  • a)
    Systematic error
  • b)
    Gross error
  • c)
    Random error
  • d)
    None of the mentioned
Correct answer is option 'B'. Can you explain this answer?

Gross errors are mostly due to lack of knowledge, judgment and care on the part of experiment. That is Gross error is caused by careless handling.

1 fermi is equal to:
  • a)
    10-10 m
  • b)
    1010 m
  • c)
    1015 m
  • d)
    10-15 m
Correct answer is option 'D'. Can you explain this answer?

Rohit Shah answered
One fermi or femtometre is equal 10^-15 m. This unit is used to measure nuclear dimensions.

The accuracy in the measurement of time for 20 oscillations of pendulum for the following measurements, t1 = 39.6 s, t2 = 39.9 s and t3 = 39.5 s is:
  • a)
    ± 0.005 s
  • b)
    ± 0.3 s
  • c)
    ± 0.5 s
  • d)
    ± 0.4 s
Correct answer is option 'A'. Can you explain this answer?

Niharika Nair answered
Given,
t1 = 39.6 s
t2 = 39.9s
t3 = 39.5 s
Least count of measuring instrument = 0.1 s
[As measurements have only one decimal place] Percision in the measurement  = Least count of the measuring instrument =0.1 s
Mean value of time for 20 oscillations
Absolute errors in the measurements
Δt1 = t - t1 = 39.7 - 39.6 = 0.1s
Δt2 = t - t2 = 39.7 - 39.9 = -0.2 s
Δt3 = t - t3 = 39.7 - 39.5 = 0.2 s
Mean absolute error
(rounding-off upto decimal place)
∴ Accuracy of measurement = ±0.2 s

 Which of the following is caused by careless handling?
  • a)
    Systematic error
  • b)
    Gross error
  • c)
    Random error
  • d)
    None of the mentioned
Correct answer is 'B'. Can you explain this answer?

.mie. answered
Ys the answr is B ... as systematic errors arises due to faulty instruments.... random errors are those errors, which occur irregularly and hence are random. These can arise due to random and unpredictable fluctuations in experimental conditions For example, when the same person repeats the same observation, it is very likely that he may get different readings every time... Gross Errors: This category basically takes into account human oversight and other mistakes while reading, recording and the readings ...(^_^)

Can you explain the answer of this question below:

 Approximate ratio of 1 fermi to 1 angstrom is …

  • A:

    10-5m

  • B:

    10-15m

  • C:

    10-9m

  • D:

    10-6m

The answer is a.

Bhargavi Bajaj answered
To find the approximate ratio of 1 fermi to 1 angstrom, we need to convert both units to a common unit of length.

1 fermi (fm) is a unit of length in the metric system, and it is equal to 10^-15 meters (m).

1 angstrom (Å) is also a unit of length in the metric system, and it is equal to 10^-10 meters (m).

To find the ratio, we can divide 1 fermi by 1 angstrom:

Ratio = 1 fm / 1 Å

Since both units are in meters, we can convert the units before dividing:

Ratio = (1 fm / 10^-15 m) / (1 Å / 10^-10 m)

Simplifying the expression:

Ratio = (1 fm * 10^-10 m) / (1 Å * 10^-15 m)

Ratio = 10^-10 / 10^-15

Using the rules of exponents, we can subtract the exponents:

Ratio = 10^5

Therefore, the approximate ratio of 1 fermi to 1 angstrom is 10^5.

What is the number of significant figures in 0.310×103 ?
  • a)
    6
  • b)
    2
  • c)
    4
  • d)
    3
Correct answer is option 'D'. Can you explain this answer?

Suresh Kumar answered
10^ powers are not considered as significant figures....
& in the case of decimal points....the zero present at the beginning & in between the numbers is considered as significant digit....
Hence;in this case the significant figures are 3...

Chapter doubts & questions for Measurement - Physics 2025 is part of Grade 9 exam preparation. The chapters have been prepared according to the Grade 9 exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for Grade 9 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.

Chapter doubts & questions of Measurement - Physics in English & Hindi are available as part of Grade 9 exam. Download more important topics, notes, lectures and mock test series for Grade 9 Exam by signing up for free.

Physics

307 videos|482 docs|202 tests

Top Courses Grade 9