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A heating element connected to a 110 V supply draws a current of 2.5 A. Calculate the electrical energy consumed by the element in 30 minutes.
8.25 kJ
495 kJ
275 kJ
16.5 kJ
495 kJ
The electrical energy consumed by a heating element is determined by the product of its voltage, current, and the total operational time. By substituting the given values into the energy formula, the total energy consumed evaluates to 495┬аkJ.
The electrical energy consumed by a heating element is determined by the product of its voltage, current, and the total operational time. By substituting the given values into the energy formula, the total energy consumed evaluates to 495┬аkJ.
Think of a water pump: the voltage is the pressure pushing the water, the current is the flow rate of the water, and the energy consumed is the total volume of water pumped over a specific duration.
Remember 'VIT' for energy: Energy equals Voltage ├Ч Current ├Ч Time (E=V├ЧI├Чt).
E=V├ЧI├Чt тАФ Electrical energy formula
P=V├ЧI тАФ Electric power formula
Electrical power is defined as the rate at which electrical energy is transferred, given by P=V├ЧI. Total electrical energy (E) is the product of power and time (t), expressed as E=P├Чt=V├ЧI├Чt. Converting time into standard SI units (seconds) yields energy in Joules, which can then be converted into kilojoules.
Voltage (V) = 110┬аV
Current (I) = 2.5┬аA
Time (t) = 30┬аminutes=30├Ч60=1800┬аseconds
Energy (E) = 110├Ч2.5├Ч1800=495,000┬аJ=495┬аkJ
Allows accurate calculation of electricity consumption and operational costs for appliances.
Calculating power consumption of household heating appliances like immersion rods and electric heaters.
Designing electrical circuits and fuses.
Always convert time from minutes to seconds when calculating energy in Joules (Watt-seconds).
Option C (275┬аkJ) results if time is incorrectly treated as 1┬аs or if only power is calculated without multiplying by time.
B is correct тАФ The electrical energy consumed by the heating element is 495┬аkJ.
In competitive exams, always watch out for unit mismatchesтАФensure time is converted to seconds and energy is appropriately scaled between Joules and kilojoules.