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4 years ago

Why is a cathode ray tube connected to a vacuum pump?

1 answer:

7 0

If the cathode ray tube is not evacuated, the electrons emitted collide with the air molecules and cannot reach the screen effectively. Therefore, the CRT is connected to a vacuum pump to remove air.

You might be interested in

How much current will pass through a 12.5 ohm resistor when it is connected to ta 115 volt source of electrical potential?

Marrrta [24]

Answer:

9.2 amperes

Explanation:

Ohm's law states that the voltage V across a conductor of resistance R is given by $V = R I$

Here, voltage V is proportional to the current I.

For voltage, unit is volts (V)

For current, unit is amperes (A)

For resistance, unit is Ohms (Ω)

Put R = 12.5 and V = 115 in V=RI

$115=12.5I\\I=\frac{115}{12.5}\\ =9.2\,\,amperes$

8 0

3 years ago

Valence electrons determine an atom’s __________. a. mass c. atomic number b. chemical properties d. period Please select the be

Lemur [1.5K]

Hello,

Here is your answer:

The proper answer to this question is option B "<span>chemical properties".

Here is how:

</span>Electrons determine a atoms chemical properties mainly what its made of.

Your answer is B.

If you need anymore help feel free to ask me!

Hope this helps!

5 0

3 years ago

Read 2 more answers

SCALCET8 3.9.018.MI. A spotlight on the ground shines on a wall 12 m away. If a man 2 m tall walks from the spotlight toward the

Firlakuza [10]

Answer:

The length of his shadow is decreasing at a rate of 1.13 m/s

Explanation:

The ray of light hitting the ground forms a right angled triangle of height H, which is the height of the building and width, D which is the distance of the tip of the shadow from the building.

Also, the height of the man, h which is parallel to H forms a right-angled triangle of width, L which is the length of the shadow.

By similar triangles,

H/D = h/L

L = hD/H

Also, when the man is 4 m from the building, the length of his shadow is L = D - 4

So, D - 4 = hD/H

H(D - 4) = hD

H = hD/(D - 4)

Since h = 2 m and D = 12 m,

H = 2 m × 12 m/(12 m - 4 m)

H = 24 m²/8 m

H = 3 m

Since L = hD/H

and h and H are constant, differentiating L with respect to time, we have

dL/dt = d(hD/H)/dt

dL/dt = h(dD/dt)/H

Now dD/dt = velocity(speed) of man = -1.7 m/s ( negative since he is moving towards the building in the negative x - direction)

Since h = 2 m and H = 3 m,

dL/dt = h(dD/dt)/H

dL/dt = 2 m(-1.7 m/s)/3 m

dL/dt = -3.4/3 m/s

dL/dt = -1.13 m/s

So, the length of his shadow is decreasing at a rate of 1.13 m/s

5 0

3 years ago

A car accelerates from rest to 19 m/s in 6 seconds. What is the acceleration of the car?

choli [55]

Answer:

the car is moving so that how it gos so fast

Explanation:

7 0

3 years ago

In an engine, an almost ideal gas is compressed adiabatically to half its volume. In doing so, 1850 J of work is done on the gas

Oliga [24]

Answer:

The value of change in internal l energy of the gas = 1850 J

Explanation:

Work done on the gas (W) = - 1850 J

Negative sign is due to work done on the system.

From the first law we know that Q = Δ U + W ------------- (1)

Where Q = Heat transfer to the gas

Δ U = Change in internal energy of the gas

W = work done on the gas

Since it is adiabatic compression of the gas so heat transfer to the gas is zero.

⇒ Q = 0

So from equation (1)

⇒ Δ U = - W ----------------- (2)

⇒ W = - 1850 J (Given)

⇒ Δ U = - (- 1850)

⇒ Δ U = + 1850 J

This is the value of change in internal energy of the gas.

6 0

3 years ago