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Vesna [10]
3 years ago
8

If light moves at a speed of 299,792,458 m/s, how long will it take light to move a distance of 1,000 km

Physics
1 answer:
astra-53 [7]3 years ago
6 0

Answer:

change 1000km into Metre

1000km=1000000 M

speed= distance/time

time=distance/speed

time=1000000/299792458

time= 0.0033second

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What are the differences between refraction and diffraction?
Liula [17]
Refraction is the change in direction of a wave.
Diffraction is the bending of a wave around a barrier.
5 0
4 years ago
A fire engine is moving south at 35 m/s while blowing its siren at a frequency of 400 Hz.
vodomira [7]

To solve this problem we will apply the concepts related to the Doppler effect. The Doppler effect is the change in the perceived frequency of any wave movement when the emitter, or focus of waves, and the receiver, or observer, move relative to each other. Mathematically it can be described as

f_d= f_s \frac{(v+v_d)}{(v-v_s)}

Here,

f_d=frequency received by detector

f_s=frequency of wave emitted by source

v_d=velocity of detector

v_s=velocity of source

v=velocity of sound wave

Replacing we have that,

f_d = 400(\frac{(343+18)}{(343-35)})

f_d=422 Hz

Therefore the frequencty that will hear the passengers is 422Hz

8 0
4 years ago
A kettle is rated at 1 kW, 220 V. Calculate the working resistance of the kettle.
Anna [14]

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

5 0
3 years ago
A phoneme is the largest unit of sound in a word.
lukranit [14]

This question is incomplete; here is the complete question:

A phoneme is the largest unit of sound in a word. Please select the best answer from the choices provided

A. T

B. F

The correct answer to this question is F (False)

Explanation:

The word "phoneme" is used to refer to the minimal unit of sound in words, and therefore in language. For example, the first phoneme in the word "man" is "m". These units of sound are essential in language because they make each word unique in meaning and sound. For example, "fan" and "man" are different due to the phonemes "m" and "f". According to this, the phone is not the largest unit of sound but the smallest unit.

7 0
3 years ago
Read 2 more answers
How much heat is needed to change the temperature of 3 grams of gold (c = 0.129 ) from 21°C to 363°C? The answer is expressed to
Temka [501]

Q= mcΔT

Where Q is heat or energy

M is mass, c is heat capacitance and t is temperature

You have to convert Celsius into kelvin in order to use this formula I believe

Celsius + 273 = Kelvin

21 + 273 = 294K

363 + 273 = 636K

Now...

Q= (0.003)(0.129)(636-294)

Q= 0.132 J if you are using kilograms, in terms of grams which seems more appropriate the answer would be 132J of energy.  

3 0
3 years ago
Read 2 more answers
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