Resistance & Resistivity

The cell has internal resistance, r, and electromotive force of 1.5 V.
What is the reading of voltmeter when the switch is closed?

• More than 3.0 V
• Less than 1.5 V
• More than 1.5 V
• 1.5 V

The circuit that can determine the electromotive force of the battery is

• A
• B
• C
• D

A battery has an e.m.f of 6.0 V. When it is connected to an external resistor, the potential different is 2.6 V and the current is 0.6 A. 
What is the value of the internal resistance?

• 3.4 Ω
• 4.3 Ω
• 4.4 Ω
• 5.7 Ω

What is the internal resistance of the battery in the circuit?

• 9.40 Ω
• 11.50 Ω
• 12.50 Ω
• 13.50 Ω

A battery of e.m.f. 12.0 V, with an internal resistance of 3.0 Ω, is connected in series with a 15.0 Ω resistor and a battery of e.m.f. 9.0 V, which has an internal resistance of 2.0 Ω. Calculate the potential difference of the 15Ω resistor.

• 15.75V

• 5.25V

• 15.25V

• 15.50V

The circuit in Figure 1 is used to investigate how the potential difference V between the terminals of a cell varies as the current I in the circuit changes. Figure 2 shows the graph of the results.

Which one of the following can be deduced from the slope of the graph?

• The internal resistance of the cell

• The e.m.f. of the cell

• The power dissipated by the cell

• The resistance of the variable resistor

The nichrome wire has a cross-sectional area of 1.3 × 10^–7 m² . Resistivity of nichrome = 1.1 × 10^–6Ωm and a resistance of 53Ω. The length of the wire is

• 0.63m

• 63m

• 0.0063m

• 6.3m

A cylindrical conductor of length l, diameter D, and resistivity ρ has a resistance R. What is the resistance of another cylindrical conductor of length l, diameter D/2 , and resistivity ρ?

• 8R

• 4R

• 2R

• R

Two resistors R1 and R2 are made of wires of the same material. The wire used for R1 has half the diameter and is twice as long as the wire used for R2.

What is the value of the ratio resistance of R1 / resistance of R2?

• 8

• 4

• 1

• 0.5