7. If the speed of light in medium-1 and medium-2 are 2.5x 10 m/s and 2x 10 m/s respectively then the refractive index of medium-1 with respect to medium-2 is (a) 3/2.5 (b) 2/2.5 (c) 2.5/3​

Answer:

[tex]15\%[/tex].

Explanation:

The efficiency of a machine is the percentage of energy input that was turned into useful energy.

The power rating of this lamp is [tex]40\; \rm W[/tex] (same as [tex]40\; \rm J \cdot s^{-1}[/tex],) meaning that [tex]40\; \rm J[/tex] of energy is supplied to this lamp every second.

The question states that [tex]34\; \rm J[/tex] out of that [tex]40\; \rm J[/tex] of energy input would be turned into heat, which is not useful energy output in this scenario. Assuming that all other forms of energy loss is negligible. The rest of the [tex](40\; \rm J - 34\; \rm J) = 6\; \rm J[/tex] of energy supplied to this lamp would be turned into useful energy output.

Thus, every second, this lamp would receive [tex]40\; \rm J[/tex] of energy input and would outputs [tex]6\; \rm J[/tex] of useful work. The efficiency of this lamp would be:

[tex]\begin{aligned}& \text{Efficiency} \\ =\; & \frac{\text{Useful energy out}}{\text{Total energy in}} \times 100\% \\ =\; & \frac{6\; \rm J}{40\; \rm J} \times 100\%\\ =\; &15\% \end{aligned}[/tex].

Because momentum is a vector quantity, the total combined momentum of all the parts of the firecracker added together after the explosion must be the same as before the explosion. The correct answer is D

Given that a firecracker is placed in the middle of a room. This means that the firecracker is at rest. That is its momentum is equal to zero. When the firecracker is lit up, it will move in a certain velocity before it explodes. Since the total combined momentum of all the parts of the firecracker scatter in all different directions are considered, that is added up, then momentum will always be conserved. That is,

The momentum of an object before explosion will always be equal to the momentum of the object after explosion.

Because momentum is a vector quantity, in which we must consider it magnitude and direction, the best answer to this question is option D.

That is,

The total combined momentum of all the parts of the firecracker added together after the explosion must be the same as before the explosion

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Answer:

You solve it

Explanation:

Answer:

you just spin it and spin it and spin it                                                                                                                   and spin it                      

and spin it

and spin it

and spin it

and spin it

until you get mad then throw it at the wall

Explanation:

ya then you look up a vid that is called rubix cube meme and there should be a pink animal its funny you should watch it!!!!!!!!!

Answer: frosted glass

Explanation:

Answer:

C

Explanation:

Frosted Glass

Answer:

Natural light (Sun, stars.etc.) and Artificial light (Lamposts, televisions.etc.)

Hope that helps. x

Answer: astrolabe

Explanation:

Answer:

How to convert joules to kilojoules

One joule is equal to thousandth of a kilojoule:

1J = 0.001kJ

The energy in kilojoules E(kJ) is equal to the energy in joules E(J) divided by 1000:

E(kJ) = E(J) / 1000

Example

Convert 500 joules to kilojoules.

The energy E in kilojoules (kJ) is equal to 500 joules (J) divided by 1000:

E(kJ) = 500J / 1000 = 0.5kJ

Joules to kilojoules conversion table

Energy (J) Energy (kJ)

1 J 0.001 kJ

2 J 0.002 kJ

3 J 0.003 kJ

4 J 0.004 kJ

5 J 0.005 kJ

6 J 0.006 kJ

7 J 0.007 kJ

8 J 0.008 kJ

9 J 0.009 kJ

10 J 0.01 kJ

20 J 0.02 kJ

30 J 0.03 kJ

40 J 0.04 kJ

50 J 0.05 kJ

60 J 0.06 kJ

70 J 0.07 kJ

80 J 0.08 kJ

90 J 0.09 kJ

100 J 0.1 kJ

200 J 0.2 kJ

300 J 0.3 kJ

400 J 0.4 kJ

500 J 0.5 kJ

600 J 0.6 kJ

700 J 0.7 kJ

800 J 0.8 kJ

900 J 0.9 kJ

1000 J 1 kJ

2000 J 2 kJ

3000 J 3 kJ

4000 J 4 kJ

5000 J 5 kJ

6000 J 6 kJ

7000 J 7 kJ

8000 J 8 kJ

9000 J 9 kJ

10000 J 10 kJ

100000 J 100 kJ

hope it help u

itz by Riddhi

Answer:

18 neutrons

Explanation:

Potassium is nuimber 19 on periodic table, so when the mass equals 37, you simply subtract 37-19 to get 18

potassium usually has a mass of 39, so when we have potassium 37, it is two less neutrons than normal

The static friction between the block and the plane is [tex]40(\mu_s) \ N[/tex].

The given parameters:

The normal reaction on the rough surface due to weight of the block is calculated as follows;

[tex]F_n = 40 \ N[/tex]

The static friction between the block and the plane is calculated as follows;

[tex]F_s = \mu_s F_n[/tex]

where;

Thus, the static friction between the block and the plane is [tex]40(\mu_s) \ N[/tex].

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The woman-canoe system has zero initial momentum. When the woman jumps from the canoe, the total momenta of the woman and canoe is conserved, so that

0 = (49 kg) (4.5 m/s) + (78 kg) v

where v is the velocity of the canoe. Solving for v, we find

(78 kg) v = - (49 kg) (4.5 m/s)

v = - 49/78 (4.5 m/s)

v ≈ -2.8 m/s

which is to say, the boat is given a velocity of 2.8 m/s to the left.

Since acceleration is constant, we can use the formula

v² - u² = 2a ∆x

where v = final velocity, u = initial velocity, a = acceleration, and ∆x = displacement. Then

0² - (20.0 m/s)² = 2 (-4.20 m/s²) ∆x

⇒   ∆x = (20.0 m/s)² / (8.40 m/s²) ≈ 47.6 m

Only 10 Kg of secondary consumers can be supported by the ecosystem.

There exists such a thing as the 10% rule in the transfer of energy in biomass from one trophic level to another. This rule ultimately controls the mass of biomass that is available at the next higher trophic level.

This rule state that only 10% of the energy in biomass is transferred to the next trophic level. By this rule, only 10% of the energy in the plant material is transferred to the carnivore population. Therefore, only 10 Kg of secondary consumers can be supported by the ecosystem.

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Answer:

This will require 266.9 of heat energy.

Explanation:

To calculate the energy required to raise the temperature of any given substance, here's what you require:The mass of the material, m The temperature change that occurs,  ΔT The specific heat capacity of the material,

c

(which you can look up). This is the amount of heat required to raise 1 gram of that substance by 1°C.

Here is a source of values of

c for different substances:

Once you have all that, this is the equation:

Q=m×c×ΔT(Q is usually used to symbolize that heat required in a case like this.)For water, the value of c is 4.186g°C So, Q=750×4.186×85=266=858=266.858

The electromagnetic spectrum allows finding the result for the question of type of electromagnetic wave has a wavelength of 956 nm

The electromagnetic wave is an oscillation of electric fields and magnets field that sustain each other, this wave time has the characteristics that it can travel without a material medium, for which they are of extreme importance.

Consequently the spectrum of electromagnetic waves to each part has been given a different name second to its use, for example

Range                        Name  

Ultraviolet light          200 to 400 nm

Visible light               400 to 700 nm

Infrared light (heat  ) 700 nm to 1 mm

The latter is subdivided into:

 Near infrared          700 nm to 1000 nm (1 μm)

 Medium infrared        1 μm  to 30 μm

 Far infrared             50 μm to 1000 μm

It indicates that the wavelength of the measured radiation is 956 nm, therefore it is in the near infrared range.

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[tex]12~ \text{km} ~ \text{h}^{-1} = \dfrac{12 \times 1000}{3600} ~~ \text{m s}^{-1} = 3.33 ~~ \text{m s}^{-1}[/tex]

Answer:

3 1/3 or 3.3333....

Explanation:

You multiply the kilometres by 1,000 because there are 1,000 metres in a kilometre. Then you divide by 60 because there are 60 minutes per hour, and then again by 60 because 60 seconds per minute.

12,000 / 60 = 200

200 / 60 = 3.333

Answer:

3.6m/s², 18m/s

Explanation:

So according to h=1/2at², 45=1/2a*25, a=3.6m/s² (which means that it didn't happen on Earth?)

Final velocity = at = 3.6*5 = 18 m/s

Hope you could get an idea from here.

Doubt clarification - use comment section.

Answer:

The formation of sand is a physical change because some of the physical properties of the rocks change, but their identities do not. The particles of rock are rearranged as their sizes and shapes change, but their identities and total mass remain the same.

The  magnitude and direction of the force on the charge​ is -12 N opposite the electric field

To calculate the force on a charge in an electric field, we make use of the formula below.

Formula

F = E×Q .......................... Equation 1

Where:

From the question,

Given:

Substitute these values into equation 1

Note: The negative sign indicates that the force is in the direction negative of the electric field.

Hence, The  magnitude and direction of the force on the charge​ is -12 N opposite the electric field

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Answer: A edge 202694020

Explanation:

Answer:

0.76 lbs (if shoes 2lbs)

Explanation:

Gravity on Mars is only ~38% as strong as it is on Earth, so objects would only weigh ~38% of their Earth weight.

Answer:

A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base. The bases used in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T).

Answer: The velocity of what?

Answer:

Ωmass

Explanation:

If there were no dark energy in the universe, the value of Ωmass would determine the evolution and fate of the universe.

Answer:

centripetal acceleration is when an object accelerates going in a circular motion.

Answer:

1200 watt

Explanation:

P= I*V=10*120=1200watt

Answer:

I think this statement is true at least in modern day times. The world runs on nothing but technology. People use more technology instead of old school textbooks and papers. Imagine living in a world without technology… that means no cars, no trains, no devices, no machines like your stove or printer, no lights and lots more. John Wesley is 100 percent correct with this statement. Electricity is indeed the powerhouse of the universe.

Answer:

3

Explanation:

because they are pushing a body

Answer:

They must be supported by evidence.

Explanation:

Every scientific theory or scientifc claim must have scientific evidence.

Answer:

Congress designed the Clean Air Act to protect public health and welfare from different types of air pollution caused by a diverse array of pollution sources.

Explanation: