Question

The filament of a bulb has a resistance of 2.5 ohms. Calculate the current drawn by it if the voltage of the supply is 7.5V

Answer 1

$\large{\underline{\textsf{\textbf{ Given \; Information : }}}}$

• Resistance (R) = 2.5 ohms

• Voltage or P.d (V) = 7.5 V

$\large{\underline{\textsf{\textbf{ To \; Calculate :}}}}$

• Current drawn by it .(I)

$\large{\underline{\textsf{\textbf{ Calculation : }}}}$

By using ohm's law, we know that ,

$\bigstar \: \boxed{\sf {V = IR}}$

• V = Voltage or potential difference.
• I = Current
• R = Resistance

From this formula,

$\longrightarrow \sf {7.5 = I \times 2.5}$

$\longrightarrow \sf {\dfrac{7.5}{2.5} A = I }$

$\longrightarrow \sf \red {3 A = I }$

Therefore, 3 A of current is drawn by it if the voltage of the supply is 7.5V.

______________

⠀⠀⠀⠀⠀⠀⠀More Information

• Current is defined as rate of flow of charge.
• It is denoted by ( I ).
• SI unit of current is Ampere.
• Ampere is denoted by ( A ).

Some more formulae :

$\bigstar \: \boxed{\sf {I = \dfrac{Q}{t} }}$

$\bigstar \: \boxed{\sf {V = \dfrac{W}{Q} }}$

$\bigstar \: \boxed{\sf {V = IR }}$

• Q is charge and its SI unit is Coulomb ( C ).
• I is current and its SI unit is Ampere ( A ).
• t is time and its SI unit is second ( S ).
• V is potential difference and its SI unit is Volt ( V ).
• W is work done and its SI unit is Joule ( J ).
• R is resistance and its SI unit is Ohm ( Ω ).