Worksheet 8b - MATHS

Activity 1: Group work

1.1 State Ohm's Law and write the formula down, showing the relation between [tex]\(V\)[/tex] (voltage), [tex]\(I\)[/tex] (current), and [tex]\(R\)[/tex] (resistance).

1.2 Calculate the following:

a) Calculate the voltage if the current is [tex]\(5 \, \text{A}\)[/tex] and the resistance is [tex]\(4 \, \Omega\)[/tex].

b) Calculate the current if the voltage is [tex]\(1150 \, \text{V}\)[/tex] and the resistance is [tex]\(2000 \, \Omega\)[/tex].

c) If the current is [tex]\(6 \, \text{A}\)[/tex] and the voltage is [tex]\(420 \, \text{V}\)[/tex], calculate the resistance.



Answer :

Certainly! Let's go through each part of the problem step-by-step.

### 1.1 Ohm's Law
Ohm's Law states that the current running through a conductor between two points is directly proportional to the voltage across the two points, provided the temperature remains constant. The formula for Ohm's Law is:

[tex]\[ V = I \cdot R \][/tex]

where:
- [tex]\( V \)[/tex] is the voltage (in volts, V),
- [tex]\( I \)[/tex] is the current (in amperes, A),
- [tex]\( R \)[/tex] is the resistance (in ohms, Ω).

### 1.2 Calculations

#### 1.2 a) Calculate the voltage if the current is 5 A and the resistance is 46 Ω.
Given:
- [tex]\( I = 5 \, \text{A} \)[/tex]
- [tex]\( R = 46 \, \text{Ω} \)[/tex]

Using Ohm's Law:

[tex]\[ V = I \cdot R \][/tex]
[tex]\[ V = 5 \, \text{A} \cdot 46 \, \text{Ω} \][/tex]
[tex]\[ V = 230 \, \text{V} \][/tex]

So, the voltage is 230 V.

#### 1.2 b) Calculate the current, if the voltage is 1150 V and the resistance is 2000 Ω.
Given:
- [tex]\( V = 1150 \, \text{V} \)[/tex]
- [tex]\( R = 2000 \, \text{Ω} \)[/tex]

Rearranging Ohm's Law to solve for the current [tex]\( I \)[/tex]:

[tex]\[ I = \frac{V}{R} \][/tex]
[tex]\[ I = \frac{1150 \, \text{V}}{2000 \, \text{Ω}} \][/tex]
[tex]\[ I = 0.575 \, \text{A} \][/tex]

So, the current is 0.575 A.

#### 1.2 c) If the current is 6 A and the voltage is 420 V, calculate the resistance.
Given:
- [tex]\( I = 6 \, \text{A} \)[/tex]
- [tex]\( V = 420 \, \text{V} \)[/tex]

Rearranging Ohm's Law to solve for the resistance [tex]\( R \)[/tex]:

[tex]\[ R = \frac{V}{I} \][/tex]
[tex]\[ R = \frac{420 \, \text{V}}{6 \, \text{A}} \][/tex]
[tex]\[ R = 70 \, \text{Ω} \][/tex]

So, the resistance is 70 Ω.

### Summary
- The voltage if the current is 5 A and the resistance is 46 Ω is 230 V.
- The current if the voltage is 1150 V and the resistance is 2000 Ω is 0.575 A.
- The resistance if the current is 6 A and the voltage is 420 V is 70 Ω.