To determine which formula defines the unit for electrical power, we need to understand the basic relationship between electrical power, voltage, and current.
Electrical power (P) is measured in Watts (W). The relationship between power, voltage (V), and current (I) is given by the formula:
[tex]\[ P = V \times I \][/tex]
This means that power is the product of voltage and current.
Let's analyze the given options:
A. \( 1 \, \text{W} = 1 \, \text{V} \times 1 \, \text{A} \)
According to the formula \( P = V \times I \), if both the voltage and current are equal to 1, then the power would be:
[tex]\[ P = 1 \, \text{V} \times 1 \, \text{A} = 1 \, \text{W} \][/tex]
This option correctly defines the unit of electrical power as the product of voltage and current.
B. \( 1 \, \text{W} = 1 \, \text{V} \div 1 \, \text{A} \)
This option suggests that power is equal to voltage divided by current. However, this is incorrect because the correct relationship involves multiplication, not division.
C. \( 1 \, \text{W} = 1 \, \text{V} \div 1 \, \Omega \)
This option suggests a division involving ohms (unit of resistance), which does not correctly define the relationship between power, voltage, and current.
D. \( 1 \, \text{W} = 1 \, \text{V} \times 1 \, \Omega \)
This option suggests that power is equal to voltage multiplied by a resistance unit. This is also incorrect since ohms (Ω) represent resistance, not current.
Therefore, the correct formula that defines the unit for electrical power is:
[tex]\[ 1 \, \text{W} = 1 \, \text{V} \times 1 \, \text{A} \][/tex]
Thus, the correct answer is option A:
[tex]\[ \boxed{1 \, \text{W} = 1 \, \text{V} \times 1 \, \text{A}} \][/tex]
