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3 years ago

What are three ways in which people use microwaves?

Physics

2 answers:

Art [367]3 years ago

5 0

to transmit data

to transmit TV signals

to transmit telephone signals

to cook in microwave ovens

to use radar

sammy [17]3 years ago

4 0

To heat up leftovers, to make dinner faster or melt chocolate

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A boy throws a ball vertically up. It returns to the

NikAS [45]

Answer:

31.25 m

25m/sec

Explanation:

Given :-

Time = 5sec

V = 0 (in going up)

U = 0 (in comming down)

Find :-

H and U by which it is thrown up

Since the total time is 5 sec ,therefore half time will be taken to go up and another half will be taken to go down .

We know that ,

V = U + gt

0 = U - 10*2.5

U = 25 m/sec

Also,

V² = U² +2gs

0 = 625 - 20s

s = 625/20 = 31.25 m

7 0

3 years ago

When light of wavelength 240 nm falls on a cobalt surface, electrons having a maximum kinetic energy of 0.17 eV are emitted. Fin

dusya [7]

Answer:

(a) 5.04 eV (B) 248.14 nm (c) $1.21\times 10^{15}Hz$

Explanation:

We have given Wavelength of the light \lambda = 240 nm

According to plank's rule ,energy of light

$E = h\nu = \frac{hc}{}\lambda$

$E = h\nu = \frac{6.67\times 10^{-34} J.s\times 3\times 10^{8}m/s}{ 240\times 10^{-9} m\times 1.6\times 10^{-19}J/eV}= 5.21 eV$

Maximum KE of emitted electron i= 0.17 eV

Part( A) Using Einstien's equation

$E = KE_{max}+\Phi _{0}$ , here $\Phi _0$ is work function.

$\Phi _{0}=E - KE_{max}$ = 5.21 eV-0.17 eV = 5.04 eV

Part( B) We have to find cutoff wavelength

$\Phi _{0} = \frac{hc}{\lambda_{cuttoff}}$

$\lambda_{cuttoff}= \frac{hc}{\Phi _{0} }$

$\lambda_{cuttoff}= \frac{6.67\times 10^{-34} J.s\times 3\times 10^{8}m/s}{5.04 eV\times 1.6\times 10^{-19}J/eV }=248.14 nm$

Part (C) In this part we have to find the cutoff frequency

$\nu = \frac{c}{\lambda_{cuttoff}}= \frac{3\times 10^{8}m/s}{248.14 \times 10^{-19} m }= 1.21\times 10^{15} Hz$

5 0

3 years ago

When you measure something in meters cubed, you are measuring ____.

Shalnov [3]

I think your answer is volume

7 0

3 years ago

Read 2 more answers

A 103 kg physics professor has fallen into the Grand Canyon. Luckily, he managed to grab a branch and is now hanging 93 m below

siniylev [52]

Answer:

125.83672 seconds

Explanation:

P = Power of the horse = 1 hp = 746 W (as it is not given we have assumed the horse has the power of 1 hp)

m = Mass of professor = 103 kg

g = Acceleration due to gravity = 9.8 m/s²

h = Height of professor = 93 m

Work done would be equal to the potential energy

$W=mgh\\\Rightarrow W=103\times 9.8\times 93\\\Rightarrow W=93874.2\ J$

Power is given by

$P=\frac{W}{t}\\\Rightarrow t=\frac{W}{P}\\\Rightarrow t=\frac{93874.2}{746}\\\Rightarrow t=125.83672\ seconds$

The time taken by the horse to pull the professor is 125.83672 seconds

6 0

3 years ago

Which explanation best describes a wave?

Gekata [30.6K]

Answer:

C. a disturbance that travels through a medium with a transfer of energy and without a transfer of matter

Explanation:

A wave is any disturbance that transfers energy from one location to the other via a substance called medium. It is important to note that a wave only conveys energy and not matter. For example, sound wave is a type of wave that carries sound energy from one place to another via mediums such as water, air etc.

Hence, according to this question, a wave can be described as a disturbance that travels through a medium with a transfer of energy and WITHOUT A TRANSFER OF MATTER.

5 0

2 years ago