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3 years ago

Which statement about the photoelectric effect is true?

Physics

1 answer:

Ivenika [448]3 years ago

6 0

Answer: A

Explanation:

The photoelectric effect was first proposed by Einstein. He claimed that when a light wave comes in contact with an electron, it has the ability to strip that electron from its atom. It depends on how much energy the light wave is carrying, and what type of atom the light is hitting. We use the photoelectric effect in garage motion sensors.

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Two long, straight wires are separated by 0.12 m. The wires carry currents of 4.0 A in opposite directions, as the drawing indic

user100 [1]

If we have I= 7.5 A:

I think my solution might just help you answer the problem on your own:

You have the formulas correct, watch your signs and BRACKETS.

B = μ0/(2π) (Current) / (Perpendicular distance)
Since μ0=4π E -7 Tm/A, we have:
B1 = (4πE-7 Tm/A)(7.5 A)/[2π (0.030 m)] = 5E-5 T
B2 = (4πE-7 Tm/A)(-7.5 A)/[2π (0.150 m)] = -1E-1 T
So BA = B1 + B2 = ?
(It looks like you just left out the square brackets, hence multiplying Pi and 0.03 and 0.15 instead of dividing them.)

For the point B, the two distances are -0.060 m and +0.060 m. Be careful with the signs. Unlike point A, the two components will have the same sign.

3 0

3 years ago

Read 2 more answers

A copper transmission cable 140 {\rm km} long and 12.5 {\rm cm} in diameter carries a current of 115 {\rm A}.

SpyIntel [72]

Answer:

1. $V=22.0407\ V$

2. $Q=9126837\ J$

Explanation:

Given:

length of copper cable, $l=140\ km=1.4\times 10^5\ m$

diameter of copper cable, $d=12.5\ cm=0.125\ m$

current through the copper wire, $i=115\ A$

We have the resistivity of copper, $\rho=1.68\times10^{-8}\ \Omega.m$

We know that the resistance of a wire is given as:

$R=\rho.\frac{l}{a}$

where:

$a=$ cross sectional area of the wire

$R=1.68\times 10^{-8}\times\frac{140000}{\pi.\frac{0.125^2}{4} }$

$R=0.1917\ \Omega$

Now from the Ohm's law:

$V=R.i$

$V=0.1917\times 115$

$V=22.0407\ V$

From the Joules law the thermal energy generated as an effect of electrical energy is mathematically given as:

$Q=i^2.R.t$

where:

$t=$ time duration for which the current flows

$Q=115^2\times 0.1917\times 3600$ (∵ we have 3600 seconds in 1 hour)

$Q=9126837\ J$

5 0

3 years ago

A 5.00 kilogram block slides along a horizontal,frictionless surface at 10.0 meters per second. for 4.00 seconds. The magnitude

finlep [7]

In this question a lot of information's are provided. Among the information's provided one information and that is the time of 4 seconds is not required for calculating the answer. Only the other information's are required.
Mass of the block that is sliding = 5.00 kg
Distance for which the block slides = 10 meters/second
Then we already know that
Momentum = Mass * Distance travelled
= (5 * 10) Kg m/s
= 50 kg m/s
So the magnitude of the blocks momentum is 50 kg m/s. The correct option among all the given options is option "b".

5 0

3 years ago

If you pull on a box with a force of 5 N and your teacher pulls on the same box with a force of 5 N in the opposite direction, t

antiseptic1488 [7]

Answer:

A. 0N

Explanation:

assume you're pulling in the positive direction, then we have 5 + (-5) = netforce = 0N

6 0

2 years ago

What weather condition creates a tornado?

AnnZ [28]

Answer:

Tornadoes form in unusually violent thunderstorms when there is sufficient (1) instability and (2) wind shear present in the lower atmosphere. Instability refers to unusually warm and humid conditions in the lower atmosphere, and possibly cooler than usual conditions in the upper atmosphere.

Explanation:

please don't delete my answer brainly i beg you

5 0

3 years ago