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Units and Measurement

11th Class - CBSE - Physics - 2754 Questions - 0 Concepts

Important Questions

Q1 Subjective Hard
The edge of a cube is measured using a vernier callipers. [9 divisions of the main scale is equal to 10 divisions of vernier scale and 1 main scale division is 1 mm]. The main scale division reading is 10 and 1 division of vernier scale was found to be coinciding with the main scale. The mass of the cube is 2.736 gm. Calculate the density in $$\mathrm{g}\mathrm{m}/\mathrm{c}\mathrm{m}^{3}$$ up to correct significant figures. 

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Q2 Single Correct Hard
From the following combinations of physical constants (expressed through their usual symbols) the only combination, that would have the same value in different system of units, is:
  • A. $$\dfrac {ch}{2\pi \epsilon_{0}^{2}}$$
  • B. $$\dfrac {e^2}{2\pi \epsilon_0Gm_{e}^{2}}(m_e=$$ mass of electron)
  • C. $$\dfrac {\mu_0 \epsilon_0}{c^2}\dfrac {G}{he^2}$$
  • D. $$\dfrac {2\pi \sqrt {\mu_0\epsilon_0}}{ce^2}\dfrac {h}{G}$$

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Q3 Subjective Hard
To find the value of g using simple pendulum, $$T = 2.00 s$$ and $$l = 1.00 m$$ were measured. Estimate maximum permissible error in g. Also find the value of g.

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Q4 Single Correct Hard
If the velocity of light $$C$$, the universal gravitational constant $$G$$, and Planck's constant $$h$$ are chosen as fundamental units, the dimension of mass in this system are
  • A. $$h^{1/2}C^{1/2}G^{-1/2}$$
  • B. $$h^{-1}C^{-1}G$$
  • C. $$hCG^{-1}$$
  • D. $$hCG$$

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Q5 Subjective Hard
If  velocity (V), force (F) and time (T) are chosen as fundamental quantities, express (a) mass and (b) energy in terms of V, F and T.

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Q6 Multiple Correct Hard
Multiple Correct Answers Type
Which of the following pairs have the same dimensions?
(L = inductance, C = capacitance, R = Resistance)
  • A. $$\dfrac{L}{R}$$ and CR
  • B. LR and CR
  • C. $$\dfrac{L}{R}$$ and $$\sqrt{LC}$$
  • D. RC and $$\dfrac{1}{LC}$$

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1 Verified Answer | Published on 18th 08, 2020

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Q7 Single Correct Hard
Two plates have lengths measured as $$(1.9 \pm  0.3)m$$ and $$(3.5 \pm0.2)m$$. Calculate their combined length with error limits.
  • A. $$(5.4 \pm 0.5)m$$
  • B. $$(5.4 \pm 2.5)m$$
  • C. $$(4.4 \pm 0.5)m$$
  • D. $$(5.4 \pm 1.5)m$$

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1 Verified Answer | Published on 18th 08, 2020

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Q8 Subjective Hard
In Searle's experiment to find Young's modulus, the diameter of wire is measured as $$D = 0.05cm$$, the length of wire is $$L = 125 cm, $$ and when a weight, $$m = 20 kg$$ is the put, extension in wire was found to be $$0.100 cm$$. Find the maximum permissible error in Young's modulus (Y).

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1 Verified Answer | Published on 18th 08, 2020

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Q9 Single Correct Hard
With due regard to significant figures, add the following:
a. 953 and 0.324
b. 953 and 0.625
c. 953.0 and 0.324
d. 953.0 and 0.374
  • A. a. $$953$$; b. $$954$$ c. $$953.3$$ d. $$953.4$$
  • B. a. $$953$$; b. $$955$$ c. $$953.3$$ d. $$953.4$$
  • C. a. $$952$$; b. $$954$$ c. $$953.3$$ d. $$953.4$$
  • D. a. $$953$$; b. $$954$$ c. $$953.3$$ d. $$952.4$$

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1 Verified Answer | Published on 18th 08, 2020

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Q10 Subjective Hard
In an experiment, the following observations were recorded:
$$L = 2.820 m, M = 3.00 kg, l = 0.087 cm$$, diameter $$D = 0.041 cm$$. Taking $$g = 9.81 m s^{-2}$$ and using the formula, Y =$$ \frac{4Mg}{\pi D^2 l}$$, find the maximum permissible error in Y.

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Subjects 8
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