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Harrizon [31]
3 years ago
10

Lithium was one of the metals studied by the American physicist Robert Millikan in his research on the photoelectric effect. Whe

n illuminated with blue light of frequency 6.64 × 10 14 Hz, the photoelectrons ejected from a lithium surface have a maximum kinetic energy of 0.332 eV. What is the threshold frequency for lithium? For this problem, let the value of Planck's constant, h, be 6.63 × 10 -34 J·s.
Physics
1 answer:
serg [7]3 years ago
3 0

Answer:

Explanation:the answer is 10

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If the diameter of the space station is 730 m , how many revolutions per minute are needed for the "artificial gravity" accelera
nignag [31]
For circular motion we know that

<span>F=ma=v^2/r </span>

<span>Therefore: </span>

<span>v = sqrt (rma) </span>

<span>Also, for cicular motion: </span>

<span>rev/min. = 60v/(2r*pi) </span>

<span>So your equation is: </span>

<span>rev./min = 60sqrt(rma)/(2pi*r) </span>

<span>For the mass (m) we can just use 1 kg. 
</span>
rev./min = 60sqrt(730*1*9.8)/(2pi*730) =60sqrt(7154)/(4584.4) 
rev./min = 60sqrt(7154)/(4584.4) =1.11 rev/min
<span>
the answer is </span>1.11 rev/min<span>

 </span>
4 0
3 years ago
The most important barriers to diffusion today are physical features of Earth's surface.
nikdorinn [45]

Answer:

False

Explanation:

Physical features of earth's surface like mountains, deserts and oceans are not the barriers in today's modern world. Technological improvements in the transportation and communication has removed these barriers. So they are not barriers anymore.

7 0
3 years ago
Which is the correct formula for finding the frequency of an electromagnetic wave? f = c – f = f = + c f =
liubo4ka [24]
The answer for the online test is going to be the last one, D
6 0
3 years ago
A disc with a mass of 1 kg moves horizontally to the right with a speed of 7 m/s on a table with negligible friction when it col
Elodia [21]

Answer:

1.6 m/s

Explanation:

First you need to find the momentums of each disc by multiplying their velocities with mass.

disc 1: 7*1= 7 kg m/s

disc 2: 1*9= 9 kg m/s

Second, you need to find the total momentum of the system by adding the momentums of each sphere.

9+7= 16 kg m/s

Because momentum is conserved, this is equal to the momentum of the composite body.

Finally, to find the composite body's velocity, divide its total momentum by its mass. This is because mass*velocity=momentum

16/10=1.6

The velocity of the composite body is 1.6 m/s.

7 0
3 years ago
1. A kangaroo hops 84 m to the east in 7 seconds.
DENIUS [597]

Explanation:

Given parameters:

Distance hopped  = 84m

Displacement  = 84m due east

Time  = 7s

Unknown:

Speed of kangaroo  = ?

Velocity of kangaroo  = ?

Solution:

To solve this problem,

    Speed  = \frac{distance}{time }   = \frac{84}{7}  = 12m/s

  Velocity  = \frac{displacement}{time}   = \frac{84}{7}   = 12m/s due east

3 0
3 years ago
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