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4 years ago

___________ of electromagnetic radiation is visible to the human eye. All A narrow portion The white color The dark colo

Physics

2 answers:

pickupchik [31]4 years ago

4 0

The answer is B) A narrow portion.

Nonamiya [84]4 years ago

3 0

Answer:

A narrow portion

Explanation:

Electromagnetic radiation are formed of electromagnetic waves. These electromagnetic waves include radio waves, microwaves, infrared waves, visible light, ultraviolet waves, X-rays, gamma rays. From all these different frequencies of lights only visible light is visible from human eyes. Visible light acquire very small section of electromagnetic waves,

So, a narrow portion of electromagnetic radiation is visible to the human eye.

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A sled of mass m is coasting on the icy surface of a frozen river. While it is passing under a bridge, a package of equal mass m

sweet [91]

Answer:B

Explanation:

Given

mass of Sled is m

another package of mass m is thrown on it

Suppose u be the initial velocity of sled

conserving momentum

$mu=2mv$

$v=\frac{u}{2}$

where v is the final velocity

Initial kinetic energy $=\frac{1}{2}mu^2$

Final Kinetic Energy $=\frac{1}{2}(2m)\cdot (\frac{u}{2})^2$

Final Kinetic Energy $=\frac{1}{2}\times \frac{1}{2}mu^2$

Final kinetic Energy is half of initial

5 0

3 years ago

Calculate the energy, wavelength, and frequency of the emitted photon when an electron moves from an energy level of -3.40 eV to

jasenka [17]

Answer:

(a) The energy of the photon is 1.632 x $10^{-8}$ J.

(b) The wavelength of the photon is 1.2 x $10^{-17}$ m.

Explanation:

Let;

$E_{1}$ = -13.60 ev

$E_{2}$ = -3.40 ev

(a) Energy of the emitted photon can be determined as;

$E_{2}$ - $E_{1}$ = -3.40 - (-13.60)

= -3.40 + 13.60

= 10.20 eV

= 10.20(1.6 x $10^{-9}$ )

$E_{2}$ - $E_{1}$ = 1.632 x $10^{-8}$ Joules

The energy of the emitted photon is 10.20 eV (or 1.632 x $10^{-8}$ Joules).

(b) The wavelength, λ, can be determined as;

E = (hc)/ λ

where: E is the energy of the photon, h is the Planck's constant (6.6 x $10^{-34}$ Js), c is the speed of light (3 x $10^{8}$ m/s) and λ is the wavelength.

10.20(1.6 x $10^{-9}$ ) = (6.6 x $10^{-34}$ * 3 x $10^{8}$ )/ λ

λ = $\frac{1.98*10^{-25} }{1.632*10^{-8} }$

= 1.213 x $10^{-17}$

Wavelength of the photon is 1.2 x $10^{-17}$ m.

E = hf

where f is the frequency of the photon.

1.632 x $10^{-8}$ = 6.6 x $10^{-34}$ x f

f = $\frac{1.632*10^{-8} }{6.6*10^{-34} }$

= 2.47 x $10^{25}$ Hz

Frequency of the emitted photon is 2.47 x $10^{25}$ Hz.

6 0

3 years ago

two cars are moving at constant speeds in a straight line along a major highway. The first is travelling at 20ms^-1 and the seco

Reika [66]

Answer:

$t=750s$

Explanation:

The two cars are under an uniform linear motion. So, the distance traveled by them is given by:

$\Delta x=vt\\x_f-x_0=vt\\x_f=x_0+vt$

$x_f$ is the same for both cars when the second one catches up with the first. If we take as reference point the initial position of the second car, we have:

$x_0_1=6km\\x_0_2=0$

We have $x_f_1=x_f_2$ . Thus, solving for t:

$x_0_1+v_1t=x_0_2+v_2t\\x_0_1=t(v_2-v_1)\\t=\frac{x_0_1}{v_2-v_1}\\t=\frac{6*10^3m}{28\frac{m}{s}-20\frac{m}{s}}\\t=750s$

8 0

3 years ago

A skydiver free falls from rest. How long does it take for the skydiver to reach 7 m/s?

aev [14]

Answer:

The skydiver needs 0.71 seconds to reach 7 m/s

Explanation:

Free Fall Motion

When an object is dropped in free air (no friction) from a certain height h, it follows a free-fall motion, whose acceleration is due exclusively to gravity. The speed at a moment t when the object is dropped (from rest) is:

$V_f=gt$