All categories

3 years ago

Why do you see objects when you shine a flashlight in a dark room?

Physics

1 answer:

anzhelika [568]3 years ago

8 0

Explanation:

We see objects in a dark room due to the emission of light photons which are sensitive to our eyes.

Darkness is simply a terminology used to describe the absence of light. Visible light to human is a component of the electromagnetic spectrum. Our eyes have receptors that picks the photons which light releases.

The particles of light are called photons.

When a torch is shines. It produces light due to emission of light by excitation of the metal in the bulb.
The light is in form of photons that spreads and travels in all direction in a room.
When they impinge on other bodies, they cause them to excite and release their own photons
Photons from the different parts helps to depict an object as it is.
The photo-receptors in our eyes picks up the photon and interprets it in our visual faculty.

learn more:

light waves brainly.com/question/8032392

#learnwithBrainly

You might be interested in

A leaky 12-kg bucket is lifted from the ground to a height of 15 m at a constant speed with a rope that weights 0.75 kg/m. Initi

Scrat [10]

Answer:

Approximately 5.5 kJ.

Explanation:

The mass of water in the bucket is $\rm 40\; kg$ at a height of 0 meters above the ground.
At a height of 15 meters, the mass of the water would be $\rm 0\; kg$ .

The bucket goes up at a constant rate. Also, the water leaks at a constant rate. As a result, the mass of water in the bucket changes at a constant rate as height increases.

Find the rate at which the mass of water decreases over height:

$\begin{aligned} &\text{Rate at which water leaks}\cr &= \frac{\text{Change in mass of Water}}{\text{Change in height}} \cr &= \rm \frac{40 \; kg - 0\; kg}{15\; m} \cr &= \rm \frac{40}{15}\; kg \cdot m^{-1}\end{aligned}$ .

In other words, $\displaystyle \rm \frac{40}{15}\; kg$ of water leaks out of the bucket everytime its height increases by $\rm 1\; m$ .

Hence, the mass of water at $h\; \rm m$ would be $\displaystyle 40 - \frac{40}{15}\, h$ $\rm kg$ . Write that as a function of height:

$\displaystyle m_\text{water}(h) = 40 - \frac{40}{15}\, h = \frac{40}{15} \, (15 - h)$ .

On the other hand, $(40 - h)\; \rm m$ of rope is still in the air while the bucket is at a height of $h\; \rm m$ . The mass of the rope that needs to be lifted at would thus be $0.75\; (15 - h)\; \rm kg$ .

Write that also as a function of the height of the bucket:

$\displaystyle m_\text{rope}(h) = 0.75\; (15 - h)$ .

Add the mass of the bucket:

$\displaystyle m(h) = \frac{40}{15}\, (15 - h) + 0.75\; (15 - h) + 12$ .

Simplify this expression:

$\begin{aligned} m(h) &= \frac{40}{15}\, (15 - h) + 0.75\; (40 - h) + 12 \cr &= \left(\frac{40}{15} + 0.75\right) (15 - h) + 12\end{aligned}$ .

The only two forces on the bucket are gravitational force and tension force from the rope. Since the bucket is moving at constant speed, the net force on it should be zero. The two forces must balance each other. In other words, they must act in opposite directions. Most importantly, the must be of equal magnitude. That is:

$\begin{aligned} F(h) &= W(h) \cr &= m(h) \cdot g \cr &= 9.81 \times \left(\left(\frac{40}{15} + 0.75\right) (15 - h) + 12\right)\cr &= 9.81 \times \left(\frac{40}{15} + 0.75\right) (15 - h) + 9.81 \times 12 \cr &\approx 502.763 - 33.5175\; h + 117.72 \cr &= 620.483 - 33.5175\; h\end{aligned}$ .

Integrate force over distance travelled to find work done. In this case, since the bucket is moving upwards, distance travelled is equal to height.

$\begin{aligned}W &= \int \limits_{0}^{15} (620.483 - 33.5175\; h) \, dh \cr &= \left[620.483\; h - \frac{1}{2}\times 33.5175\; h^2\right]^{15}_{0} \cr &= \left(620.483 \times 15 - \frac{1}{2} \times 33.5175 \times 15^2\right) - 0 \cr &\approx 5.5\times 10^{3}\; \rm J \cr &= 5.5\;\rm kJ \end{aligned}$ .

7 0

3 years ago

If the same net force is applied to a 7kg

sergij07 [2.7K]

(2nd variant, 7kg is 3 times faster than 21kg)

3 0

4 years ago

5000 j of heat are added to a system. it does 3500 j of work on the surroundings. what is δe in j?

Alika [10]

The Answer is 5200 Joules

3 0

3 years ago

Why do things become hot or cold? Relate to Thermal Energy and The Law of Conservation of Energy

Mekhanik [1.2K]

Answer:

Things become hot and cold because of the transfer of energy.

Explanation:

The energy possessed by an object or system is called thermal energy and heat is the flow of this energy. While the law of conversation of energy states that energy is not destroyed or created, it just transfers from one object to another.

When a hot object is placed in normal conditions, it transfers heat to the environment until both are at the same temperature and heat transfers from the environment to the cold objects placed in normal conditions.

4 0

3 years ago

Magnetic and electric fields lab report guide

Digiron [165]

Answer:

?>?

Explanation:

4 0

3 years ago

Read 2 more answers

Why do you see objects when you shine a flashlight in a dark room?​

Why do you see objects when you shine a flashlight in a dark room?