When the length and area of cross-section both are doubled, then its resistance :

1. Will become half

2. Will be doubled

3. Will remain the same

4. Will become four times

An electric wire of length ‘I’ and area of cross-section a has a resistance R ohms. Another wire of the same material having the same length and area of cross-section 4a has a resistance of :

1. 4R

2. R/4

3. R/16

4. 16R

A wire of radius r has resistance R. If it is stretched to a radius of $\frac{3r}{4}$, its resistance becomes 

1. $\frac{9R}{16}$

2. $\frac{16R}{9}$

3. $\frac{81R}{256}$

4. $\frac{256R}{81}$

Express which of the following setups can be used to verify Ohm’s law 

1.
2.
3.
4.

What is the resistance of a carbon resistance which has bands of colours brown, black and brown 

1. 100 Ω

2. 1000 Ω

3. 10 Ω

4. 1 Ω

The following four wires are made of the same material and are at the same temperature. Which one of them has highest electrical resistance :

1. Length = 50 cm, diameter = 0.5 mm

2. Length = 100 cm, diameter = 1 mm

3. Length = 200 cm, diameter = 2 mm

4. Length = 300 cm, diameter = 3 mm

The current in the adjoining circuit will be 

1. $\frac{1}{45}ampere$

2. $\frac{1}{15}ampere$

3. $\frac{1}{10}ampere$

4. $\frac{1}{5}ampere$

The reading of the ammeter as per figure shown is

1. $\frac{1}{8}A$

2. $\frac{3}{4}A$

3. $\frac{1}{2}A$

4. 2 A

A current of 2 A flows in a system of conductors as shown. The potential difference $(V_A-V_B)$ will be 

1. +2 V

2. +1 V

3. –1 V

4. –2 V