An electric motor takes 5 A from a 220 V line. Determine the power of the motor and the energy consumed in 2 h.
Power (P) is given by the expression,
P = VI
Where,
Voltage, V = 220 V
Current, I = 5 A
P = 220 x 5 = 1100 W
Energy consumed by the motor = Pt
Where,
Time, t = 2 h = 2 × 60 × 60 = 7200 s
P = 1100 × 7200 = 7.92 × 106 J
Therefore, power of the motor = 1100 W
Energy consumed by the motor = 7.92 × 106 J
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
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(iii) Butanone (iv) Hexanal.
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(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?
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Write the balanced chemical equation for the following and identify the type of reaction in each case.
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(b) Zinc carbonate(s) → Zinc oxide(s) + Carbon dioxide(g)
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(b) Switching off unnecessary lights and fans
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(c) nuclear energy (d) coal
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