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trapecia [35]
3 years ago
10

A kettle is rated at 1 kW, 220 V. Calculate the working resistance of the kettle.

Physics
1 answer:
Anna [14]3 years ago
5 0

Explanation:

Power of electric kettle, P = 1 kW

Voltage, V = 220 V

(a) Electric power is given by the formula as follows :

P=\dfrac{V^2}{R}

R is resistance

R=\dfrac{V^2}{P}\\\\R=\dfrac{(220)^2}{10^3}\\\\R=48.4\ \Omega

(b) When connected to a 220 V supply, it takes 3 minutes for the water in the kettle to reach boiling point.

Energy supplied is given by :

E=P\times t

P is power, P=\dfrac{V^2}{R}

E=\dfrac{V^2}{R}t\\\\E=\dfrac{(220)^2}{48.4}\times 180\\\\E=180000\ J\\\\E=180\ kJ

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3 years ago
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after a circuit has been turned off, so it is important to make sure they are discharged before you touch them. Suppose a 120 mF
Snezhnost [94]

Answer:

The time is 110.16\times10^{-3}\ sec

Explanation:

Given that,

Capacitor = 120 μF

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Current = 50 mA

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i_{0}=\dfrac{V_{0}}{R}

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Put the value into the formula

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\dfrac{-t}{RC}=ln(0.600)

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4 0
3 years ago
While researching scuba diving, Pablo reads how hot a tank should get while being filled with air. Which law best explains why t
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Answer:

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p\propto T

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In this case, the tank is filled with air: this means that the pressure of the gas inside the tank increases. And therefore, according to Gay-Lussac's law, the temperature will increase proportionally, and this explains why the tank gets hot.

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