Q. No.The statement “To call a dimensional quantity ‘large’ or ‘small’ is meaningless without specifying a standard for comparison” emphasizes the importance of reference standards in physics. Which of the following revised statements correctly reflects this principle?
1.
Atoms are very small objects.
2.
A jet plane moves with great speed.
3.
The mass of Jupiter is very large.
4.
A proton is about \(1836\) times more massive than an electron.
A new unit of length is chosen such that the speed of light in a vacuum is unity. What is the distance between the Sun and the Earth in terms of the new unit if light takes \(8~\text{min}\) and \(20~\text{s}\) to cover this distance?
1. \(125\)
2. \(250\)
3. \(350\)
4. \(500\)
A student measures the thickness of a human hair by looking at it through a microscope of magnification \(100.\) He makes \(20\) observations and finds that the average width of the hair in the field of view of the microscope is \(3.5~\text{mm}.\) What is the estimate of the thickness of the hair?
1. \(0.0035~\text{mm}\)
2. \(0.0350~\text{mm}\)
3. \(0.1350~\text{mm}\)
4. \(0.2350~\text{mm}\)
Consider the following statements:
| (A) | The diameter of a thread is so small that it cannot be measured using a meter scale. |
| (B) | In a screw gauge the least count decreases on increasing the number of divisions on the circular scale. |
| (C) | A large number of observations (say, 100) will give more reliable results than a smaller number of observations (say, 5). |
Choose the correct option from the given ones:
| 1. | Only statements 1 and 2 are correct |
| 2. | Only statements 2 and 3 are correct |
| 3. | All three statements are correct |
| 4. | Only statements 1 and 3 are correct |
The photograph of a house occupies an area of \(1.75~\text{cm}^2\) on a \(35~\text{mm}\)35 mm slide. The slide is projected onto a screen, and the area of the house on the screen is \(1.55~\text{m}^2.\) What is the linear magnification of the projector-screen arrangement?
1. \(84.1\)
2. \(94.1\)
3. \(74.1\)
4. \(14.1\)
How many significant figures are in \(0.0006032~\text{m}^2?\)
1. \(8\)
2. \(4\)
3. \(9\)
4. none of these
The sum of the numbers \(436.32,227.2,\) and \(0.301\) in the appropriate significant figures is:
| 1. | \( 663.821 \) | 2. | \( 664 \) |
| 3. | \( 663.8 \) | 4. | \(663.82\) |
The mass and volume of a body are \(4.237~\text{g }\) and \(2.5~\text{cm}^3,\) respectively. The density of the material of the body in correct significant figures will be:
1. \(1.6048~\text{g cm}^{-3}\)
2. \(1.69~\text{g cm}^{-3}\)
3. \(1.7~\text{g cm}^{-3}\)
4. \(1.695~\text{g cm}^{-3}\)
The numbers \(2.745\) and \(2.735\) on rounding off to \(3\) significant figures will give respectively,
| 1. | \(2.75\) and \(2.74\) | 2. | \(2.74\) and \(2.73\) |
| 3. | \(2.75\) and \(2.73\) | 4. | \(2.74\) and \(2.74\) |
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