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3 years ago

An electric heater is rated at 1500 W. If the heater is rated as 80% efficient, calculate the output

Physics

1 answer:

Nadya [2.5K]3 years ago

5 0

Answer:

Power = 1200 [W].

Explanation:

The efficiency of an electrical equipment is defined as the relationship between the power realized, over the power that is consumed. For this case, they give us the data of consumed power and efficiency in this way we can calculate the power that the equipment performs.

$Efficency=\frac{Power_{done}}{P_{consumed}}\\0.8 = \frac{Power_{done}}{1500} \\Power_{done}=1500*0.8\\Power_{done} = 1200 [W]$

This means that of the 1500 [W], 1200 [W] are actually used to get the job done. This is established by means of the first law of thermodynamics.

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Tresset [83]

Answer: 2.92 s

Explanation:

Given

Mass of ball is $m=3.9\ kg$

The initial velocity of the ball is $u=-3.5\ m/s$

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$\Rightarrow F\cdot \Delta t=m(\Delta v)$

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Scilla [17]

Answer:

A and B

Explanation:

The relation between frequency and wavelength is shown below as:

$c=frequency\times Wavelength$

c is the speed of light having value $3\times 10^8\ m/s$

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Option A is correct.

Given, Frequency = $1\times 10^{18}\ Hz$

Thus, Wavelength is:

$Wavelength=\frac{c}{Frequency}$

$Wavelength=\frac{3\times 10^8}{1\times 10^{18}}\ m$

$Wavelength=3\times 10^{-10}\ m$

Also, 1 m = $3\times 10^{-10}$ Å

So,

Wavelength = 3.0 Å

Option B is correct.

As stated above, the speed of electromagnetic radiation is constant. Hence, each radiation of the spectrum travels with same speed.

Option C is incorrect.

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