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3 years ago

If an object only reflects ultraviolet photons, what color would it look to us? white a) black b)c) redclear d)violet e)

Physics

1 answer:

xenn [34]3 years ago

4 0

Answer:

The correct answer is option 'b': Black

Explanation:

As we know that the color that our eye perceives is the color of the component of the visible light that the object reflects. It means that if an object reflects wavelength of red light when white light is incident on it it will appear to be red.

in our case it is given that the object absorbs all the wavelengths of the visible light spectrum thus it will appear as black to our eye.

Now since our eyes cannot sense the ultraviolet spectrum of light thus we cannot observe any difference if the object emitted the UV radiation or not. Hence the object will appear to be black.

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What is one way that early scientific practice differed from modern scientific practice?

mote1985 [20]

Early hypotheses were not based on observations.
Early hypotheses were not tested by experimentation.
Early hypotheses were formed from scientific questions.
Early hypotheses were influenced by creative thinking

6 0

3 years ago

Read 2 more answers

A power plant produces 1000 MW to suply a city 40Km away.Current flows from the power plant on a single wire of resistance0.050

Westkost [7]

Answer:

The current in wire resistance 2Ω

a). 8696 A

b). fraction power 15.1% a 115kV

Explanation:

Resistance

$R=0.05$ Ω/Km*40km

R=2Ω

P=1000 MW

a).

$P=V*I\\I=\frac{P}{V}=\frac{1000x10^{6}W}{115x10^{3}k } =8696.65A$

Using law ohm

b).

$V=I*R\\I=\frac{V}{R}$

$P=I*I*R\\P=I^{2} *R\\P=8696.65^{2}*2\\P=151.228 x10^{6} W$

$e=\frac{151.228x10^{6} }{1000x10^{6} }*100= 15.12$ %

8 0

3 years ago

A real battery with internal resistance 0.460 Ω and emf 9.00 V is used to charge a 56.0-µF capacitor. A 21.0-Ω resistor is put i

Margaret [11]

Answer: 1.176×10^-3 s

Explanation: The time constant formulae for an RC circuit is given below as

t =RC

Where t = time constant , R = magnitude of resistance = 21 ohms , C = capacitance of capacitor = 56 uf = 56×10^-6 F

t = 56×10^-6 × 21

t = 1176×10^-6

t = 1.176×10^-3 s

4 0

3 years ago

Read 2 more answers

A room with 3.1-m-high ceilings has a metal plate on the floor with V = 0V and a separate metal plate on the ceiling. A 1.1g gla

miss Akunina [59]

Answer:

The ball traveled 0.827 m

Explanation:

Given;

distance between the metal plates of the room, d = 3.1 m

mass of the glass, m = 1.1g

charge on the glass, q = 4.7 nC

speed of the glass ball, v = 4.8 m/s

voltage of the ceiling, V = +3.0 x 10⁶ V

The repulsive force experienced by the ball when shot to the ceiling with positive voltage, can be calculated using Coulomb's law;

F = qV/d

|F| = (4.7 x 10⁻⁹ x 3 x 10⁶) / (3.1)

|F| = 4.548 x 10⁻³ N

F = - 4.548 x 10⁻³ N

The net horizontal force experienced by this ball is;

$F_{net} = F_c - mg\\\\F_{net} = -4.548 *10^{-3} - (1.1*10^{-3} * 9.8)\\\\F_{net} = -15.328*10^{-3} \ N$

The work done between the ends of the plate is equal to product of the magnitude of net force on the ball and the distance traveled by the ball.

$W = F_{net} *h\\\\W = 15.328 *10^{-3} * h$

W = K.E

$15.328*10^{-3} *h = \frac{1}{2}mv^2\\\\ 15.328*10^{-3} *h = \frac{1}{2}(1.1*10^{-3})(4.8)^2\\\\ 15.328*10^{-3} *h =0.0127\\\\h = \frac{0.0127}{15.328*10^{-3}}\\\\ h = 0.827 \ m$

Therefore, the ball traveled 0.827 m

4 0

3 years ago

compare the theories that scientists proposed about the source of the sun's energy with the process of nuclear fusion in the sun

ANTONII [103]

The sun's source of energy is know as nuclear fusion (means to fuse) this process has a small nuclei atoms that join together to form a large nucleus. The result of this process is released energy. The fusion of hydrogen into helium in the sun makes a large amount of energy and this is known as the sun's energy source.
The theories that scientist proposed about the source of the sun's energy was that the sun burned fuel to generate its energy and that gravity was causing the sun to shrink slowly and have its energy released. Also both of these theories were disproved.
.

3 0

2 years ago