Daily Practice Problems

Class 11 Physics

Units and Measurements

Class 11 Physics

Units and Measurements

**Question 1.**

What do you understand by the ‘Fundamental units’ and ‘Derived units’?

**Question 2.**

Name different systems of units for measurement.

**Question 3.**

What is the parallax method? Explain.

**Question 4.**

How many metres in 2 light years?

**Question 5.**

Fill in the blanks:

- 1 fermi = _ m.
- 1 astronomical unit = _m.
- 1 angstrom = _m.
- 1 parsec = _m.

**Question 6.**

What do you understand by the unified atomic mass unit (u)?

**Question 7.**

Define the terms: accuracy and precision.

**Question 8.**

Differentiate between systematic errors and random errors.

**Question 9.**

What do you understand by ‘Least count error’?

**Question 10.**

What do you understand by the terms ‘Absolute error’, ‘Relative error’ and ‘Percentage error’?

**Question 11.**

The resistance R=V/I, where V= (100±4) V and I= (100±3) A. Find the percentage error in R.

**Question 12.**

The length and breadth of a rectangular park is 3.21 m. and 4.278 m. respectively. What is the area of that park to appropriate significant figures?

**Question 13.**

How do you define ‘the dimensions of the quantity’? Write down the dimensional formula for work and force.

**Question 14.**

State the number of significant figures in the following:

- 0.0008 m
^{2}. - 3.19×10
^{35}kg.

**Question 15.**

A physical quantity A is related to four observables p, q, r and s as follows:

A = p^{4}q^{2}r^{3}/s^{3}

The percentage errors of measurement in p, q, r, s is 2%, 4%, 1% and 3% respectively. What is the percentage error in the quantity A?

**Question 16.**

There are two boxes of masses 30.17 g. and 3.20 kg. respectively. Give the total mass of these two boxes to the correct significant figures.

**Question 17.**

The third equation of motion is: v^{2}=u^{2}+2as.

Check if it is dimensionally correct or not.

**Question 18.**

Write down the dimensional formula for Volume, Speed and Mass Density.

**Question 19.**

What are the seven base quantities? Make a table for their name and symbols.

**Question 20.**

Is ‘amount of substance’ a fundamental quantity? Define it. What is its symbol?

**Question 21.**

The period of oscillation of a simple pendulum is T=2∏√L/√g. Measured value of L is 25.0cm. known to 1mm. accuracy and time for 100 oscillations of the pendulum is found to be 80 sec. using a wrist watch of 1s resolution. What is the accuracy in the determination of g?

**Question 22.**

Each side of a cube is measured to be 6.534m. What are the total surface area and the volume of the cube to appropriate significant figures?

**********