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# An electric bulb is rated as $10\,W, 220\,V$. How many of these bulbs can be connected in parallel across the two wires of the $220\,V$ supply line if the maximum current which can be drawn is $5\,A$?

Last updated date: 21st Jul 2024
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Hint:In physics, power is defined as the amount of energy transferred or converted per unit time. The watt is a unit of power that is equal to one joule per second in the International System of Units. In older books, power is sometimes referred to as action.Power is a scalar quantity.

An electric current is a stream of charged particles, such as electrons or ions, flowing through an electrical conductor or vacuum. It is measured by the net rate of electric charge movement through a surface or a control volume. The ampere is the reference unit of electric current in the International System of Units. The name was assigned to André-Marie Ampère, a French mathematician and physicist generally known as the inventor of electromagnetism.

Potential energy is the energy stored within an object as a function of its position, structure, or state. Potential energy is one of the two main sources of energy, along with kinetic energy.
Since it has no direction, power is a scalar quantity. The SI unit of energy is Joules per Second (J/s), also known as Watt. The amount of energy used to do one joule of work in one second is measured in watts. So James Watt, the inventor of the steam engine, is honoured with the Watt unit.

We know that
${\mathbf{P}} = {\mathbf{VI}}$
Given, ${\text{P}} = 10\;{\text{W}},\;{\text{V}} = 220\;{\text{V}},{\text{I}} = 5\;{\text{A}}$
Substituting the values,
$P = V \times I$
$\Rightarrow P = 220 \times 5$
$\therefore P = 1100\,W$
Power of one bulb =10 W
Total number of bulbs that can be connected = $\dfrac{{1100}}{{10}} = 110$

Hence, the total number of bulbs that are connected is 110.

Note: Energy divided by time is the power dimension. The watt (W), which is equivalent to one joule per second in the International System of Units (SI), is the unit of power. Another typical and standard metric is horsepower (hp), which is equivalent to the power of a horse; one mechanical horsepower equals approximately 745.7 watts. ergs per second (erg/s), foot-pounds per minute (fpm), dBm (a logarithmic metric compared to a reference of 1 milliwatt), calories per hour, BTU per hour (BTU/h), and tonnes of refrigeration are the those units of strength.