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2 years ago

40

Physics

1 answer:

insens350 [35]2 years ago

4 0

Answer:

774.8 secs

Explanation:

distance(d)= speed(v)* time(t)

calculate speed:

refractive index = speed of light (c)/ speed of light in medium (v)

1.56 = 3*10^8*v

v=192307692.3 m/s

d = v *t

t = d/v

on substituting values:

t = 774.8 secs

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An electric pump rated 1.5 KW lifts 200kg of water through a vertical height of 6m in 10 secs: way is the efficiency of the pump

ruslelena [56]

Answer:

80%

Explanation:

Efficiency = Power output / Power input × 100 %

To calculate efficiency we need to find power output of electric pump.

We can use,

Work done = Energy change

Work done per second = Energy change per second

Work done per second = Power

Therefore, Power = Energy change per second

= Change in potential energy of water per second

=mgh / t

= 200× 10×6 / 10

= 1200 W = 1.2 kW

Now use the first equation to find efficiency,

Efficiency = $\frac{1.2}{1.5}$ × 100%

= 80 %

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3 years ago

Two in-phase loudspeakers that emit sound with the same frequency are placed along a wall and are separated by a distance of 5.0

e-lub [12.9K]

Answer:

$f = 421.8 Hz$

Explanation:

When she moved a distance of 1 m from mid point she observe first destructive interference due to two speakers

so we can say that path difference of sound due to two speakers will be equal to half of the wavelength

so path difference is given as

$\Delta L = {3.5^2 + 12^2}^{0.5} - {1.5^2 + 12^2}^{0.5}$

so it will be

$\Delta L = 12.5 - 12.093$

$\Delta L = 0.4066$

now we know that

$\frac{\lambda}{2} = 0.4066$

$\lambda = 0.813$

now frequency of sound is given as

$f = \frac{v}{\lambda}$

$f = \frac{343}{0.813}$

$f = 421.8 Hz$

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3 years ago

An unknown substance from planet X has a density of 10 g/mL. It occupies a volume of 80 mL. What is the mass of this unknown sub

asambeis [7]

Answer:

800 mL

Explanation:

D*V=M

You pick out the numbers as well as what it is they represent from the word problem/explanation, then from there plug them in to the equations. Once you do that, you get your product and have the answer.

10*80= 800

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3 years ago

20. A mass of gas has a volume of 4 m3, a temperature of 290 K, and an absolute pressure of 475 kPa. When the gas is allowed to

aliina [53]

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3 years ago

The time that an object takes to complete its orbit once around the sun

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The farther away an object is from the Sun the slower it orbits around it. The closer an object is from the Sun the faster it orbits around it.

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3 years ago