The total amount of electrical energy used by a
315-watt television during 30.0 minutes of
operation is
(1) 5.67 × 10^5 J (3) 1.05 × 10^1 J
(2) 9.45 × 10^3 J (4) 1.75 × 10^1 J



Answer :

naǫ
[tex]W=Pt[/tex]
W - energy, P - power, t - time

[tex]P=315 \ W \\ t= 30 \ min= 30 \times 60 \ s = 1800 \ s \\ \\ W=315 \times 1800=567000=5.67 \times 10^5 \ [J][/tex]

The answer is (1).

The amount of electrical energy used by the television is given by:

[tex] E=Pt [/tex]

where P is the power of the device and t is the time.


The power of the television is P=315 W, while the total time is

[tex] t=30.0 min \cdot 60 =1800 s [/tex]

If we substitute these numbers into the formula, we find the energy:

[tex] E=Pt=(315 W)(1800 s)=5.67 \cdot 10^5 J [/tex]


so, the correct answer is

(1) 5.67 × 10^5 J