Answer:

Explanation:
The energy difference between the energy levels involved in the transition of the electron is directly proportional to the frequency of the emitted photon:

Where h is the Planck constant. The photon's frequency is inversely proportional to its wavelegth:

Here c is the speed of light. Replacing (2) in (1):

Answer:
Magnetic field, 
Explanation:
Given that,
Velocity of electron, 
It enters a region of space where perpendicular electric and a magnetic fields are present.
Magnitude of electric field, 
We need to find the magnetic field will allow the electron to go through the region without being deflected.
Magnetic force on the electron,
.......(1)
Electric force on the electron, F = q E........(2)
From equation (1) and (2) we get:



B = 0.0002 T
or

Hence, this is the required solution.
Answer: The end point of a spring oscillates with a period of 2.0 s when a block with mass m is attached to it. When this mass is increased by 2.0 kg, the period is found to be 3.0 s. Then the mass m is 0.625kg.
Explanation: To find the answer, we need to know more about the simple harmonic motion.
<h3>
What is simple harmonic motion?</h3>
- A particle is said to execute SHM, if it moves to and fro about the mean position under the action of restoring force.
- We have the equation of time period of a SHM as,

- Where, m is the mass of the body and k is the spring constant.
<h3>How to solve the problem?</h3>

- We have to find the value of m,


Thus, we can conclude that, the mass m will be 0.625kg.
Learn more about simple harmonic motion here:
brainly.com/question/28045110
#SPJ4
Answer:
4 A
Explanation:
V = IR, where V=voltage, I=current, R=resistance. This is Ohm's Law. (remember that for units V = volts, Ω = ohms, A = amperes.)
V = IR
12 V = I * 3 Ω
12/3 = I
<u>I = 4 A</u>
Answer:
33.5 kJ
Explanation:
here there is no difference is made in the temperature. Only thing happens here is the conversion of the ice in to water of 0 degree. The heat energy taken from the outside is spent for this conversion.
we have ice 100g =0.1 kg
Appplying Q=mL
Q= 
Q = 33 500 J
Q = 33.5 kJ