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3 years ago

the candle had 350 J of energy in the chemical store. As it burned, 250 J was transferred by lighting to the surrounding

Physics

1 answer:

Elan Coil [88]3 years ago

4 0

Answer:

Efficiency = 71%

Explanation:

Given the following data:

Output energy = 250 Joules

Input energy = 350 Joules

To find efficiency;

$Efficiency = \frac {Out-put \; energy}{In-put \; energy} * 100$

Substituting into the equation, we have;

$Efficiency = \frac {250}{350} * 100$

$Efficiency = 0.7143 * 100$

Efficiency = 71.43 ≈ 71%

Therefore, the efficiency of the candle is 71 percent.

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3 years ago

The time constant of an RC circuit is 2.7 s. How much time t is required for the capacitor (uncharged initially) to gain 0.63 of

gayaneshka [121]

Answer:

2.7s

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3 years ago

A girl weighing 50 kgf wears sandals of pencil heel of area of cross section 1 cm^2, stands on the floor.An elephant weighing 20

Klio2033 [76]

Answer:

$\boxed{{\boxed{\blue{ 12.5}}}}$

Explanation:

Given, for girl : Weight or force;

$\rm \: F_1 = 50 \: kgf$

Area of both heels;

$\rm \: A_1 = \; 2 ×1 \; cm^2 = 2 \: cm^2$

$\rm \: Pressure \: P_1 = \cfrac{F_1}{ A_1 } = \dfrac{50 \: kgf}{2 \: cm {}^{2} } = 25 \: kgf \: cm {}^{ - 1}$

For elephant, Weight = Force $\rm F_2$ = 2000 kg•f

Area of 4 feet;

$\rm \: A_2 = \; 4 \times 250 \; cm^2 = 1000 \: cm^2$

$\rm \: Pressure \: P_2 = {F_2}/{A_2} \; = \cfrac{2 \cancel{0 00 }\: kgf}{1 \cancel{000} \: cm^2} = 2 \: kgf \: { \:cm}^{- 1}$

Now;

$\rm = \dfrac{Pressure \: Exerted \: by \: the \: Girl}{Pressure \: exerted \: by \: the \: elephant}$

$= \rm \: P_1/P_2$

$\implies \rm\cfrac{25 \: kgf \: \: cm {}^{ - 2} }{2 \: kgf \: cm {}^{ - 2} } = \rm\cfrac{25 \: \cancel{kgf \: \: cm {}^{ - 2}} }{2 \: \cancel{ kgf \: cm {}^{ - 2}} } = \boxed{12.5}$

Thus, the girl's pointed heel sandals exert 12.5 times more pressure P than the pressure P exerted by the elephant.

I aspire this helps!

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2 years ago

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the candle had 350 J of energy in the chemical store. As it burned, 250 J was transferred by lighting to the surrounding​

the candle had 350 J of energy in the chemical store. As it burned, 250 J was transferred by lighting to the surrounding