Why is a specimen smaller than 200 nm not visible with a light microscope?

What is the special name for doctors who deal with cancer?

Sladkaya [172]

Oncology is the study of cancer, so the doctors are called oncologists

8 0

3 years ago

Read 2 more answers

Which of the following statements describes a battery?

LiRa [457]

Answer:

The negative electrode of a battery has an excess of positive charge

Explanation:

This is because in every battery, there is a negative electrode ( cathode ) and only positive charge is deposited on it.

For other statements:

Batteries donot store electric charge but they store chemical energy

Some batteries donot use metals for the flow of electrons, but some use hydrogen gas at a pressure of 1 atmosphere.

8 0

3 years ago

An LED is useful because when a current passes through it, it gives out... what?

Mkey [24]

An LED is useful because when a current passes through it, it gives out light.

4 0

2 years ago

A system had 150 kj of work done on it and its internal energy increased by 60 kj. How much energy did the system gain or lose a

mina [271]

Answer:

The system loses 90 kJ of heat

Explanation:

We can answer the question by using the 1st law of thermodynamics, which states that:

$\Delta U=Q-W$

where

$\Delta U$ is the change in internal energy of the system

$Q$ is the heat absorbed by the system (positive if absorbed, negative if released by the system)

$W$ is the work done by the system (positive if done by the system, negative if done by the surrounding on the system)

In this problem, we have:

$W=-150 kJ$ is the work done (negative, because it is done by the surrounding on the system)

$\Delta U=+60 kJ$ is the increase in internal energy

Using the equation above, we can find Q, the heat absorbed/released by the system:

$Q=\Delta U+W=+60 kJ+(-150 kJ)=-90 kJ$

And the negative sign means that the system has lost this heat.

8 0

3 years ago

Suppose you design a new thermometer called the "x" thermometer. on the x scale, the boiling point of water is 130.0 ox and the

Hoochie [10]

You've told us:

-- 130°x = 212°F

and

-- 10°x = 32°F

Thank you. Those are two points on a graph of °x vs °F . With those, we can figure out the equation of the graph, and easily convert ANY temperature on one scale to the equivalent temperature on the other scale.

-- If our graph is going to have °x on the horizontal axis and °F on the vertical axis, then the two points we know are (130, 212) and (10, 32) .

-- The slope of the line through these two points is

Slope = (32 - 212) / (10 - 130)

Slope = (-180) / (-120)

Slope = 1.5

So far, the equation of the graph is

F = 1.5 x + (F-intercept)

Plug one of the points into this equation. I'll use the second point (10, 32) just because the numbers are smaller:

32 = 1.5 (10) + F-intercept

32 = 15 + (F-intercept)

F-intercept = 17

So the equation of the conversion graph is

F = 1.5 x + 17

There you are ! Now you can plug ANY x temperature in there, and the F temperature jumps out at you.

The question is asking what temperature is the same on both scales. This seems tricky, but it's not too bad. Whatever that temperature is, since it's the same on both scales, you can take the conversion equation, and write the same variable in BOTH places.

We can write [ x = 1.5x + 17 ], solve it for x, and the solution will be the same temperature in F too.

or

We can write [ F = 1.5F + 17 ], solve it for F, and the solution will be the same temperature in x too.

F = 1.5F + 17

Subtract F from each side: 0.5F + 17 = 0

Subtract 17 from each side: 0.5F = -17

Multiply each side by 2 : F = -34

That should be the temperature that's the same number on both scales.

Let's check it out, using our handy-dandy conversion formula (the equation of our graph):

F = 1.5x + 17

Plug in -34 for x:

F = 1.5(-34) + 17

F = -51 + 17

It works ! -34 on either scale converts to -34 on the other one too. If the temperature ever gets down to -34, and you take both thermometers outside, they'll both read the same number.

6 0

3 years ago