Answer:
A and B
Explanation:
The relation between frequency and wavelength is shown below as:

c is the speed of light having value 
Thus, the product of the wavelength and the frequency is constant and equal to 
<u>Option A is correct.</u>
Given, Frequency = 
Thus, Wavelength is:



Also, 1 m =
Å
So,
<u>Wavelength = 3.0 Å</u>
<u>Option B is correct.</u>
As stated above, the speed of electromagnetic radiation is constant. Hence, each radiation of the spectrum travels with same speed.
<u>Option C is incorrect.</u>
Answer:
A. 2.82 eV
B. 439nm
C. 59.5 angstroms
Explanation:
A. To calculate the energy of the photon emitted you use the following formula:
(1)
n1: final state = 5
n2: initial state = 2
Where the energy is electron volts. You replace the values of n1 and n2 in the equation (1):

B. The energy of the emitted photon is given by the following formula:
(2)
h: Planck's constant = 6.62*10^{-34} kgm^2/s
c: speed of light = 3*10^8 m/s
λ: wavelength of the photon
You first convert the energy from eV to J:

Next, you use the equation (2) and solve for λ:

C. The radius of the orbit is given by:
(3)
where ao is the Bohr's radius = 2.380 Angstroms
You use the equation (3) with n=5:

hence, the radius of the atom in its 5-th state is 59.5 anstrongs
Answer:
a) 37.8 W
b) 2 Nm
Explanation:
180 g = 0.18 kg
We can also convert 180 revolution per minute to standard angular velocity unit knowing that each revolution is 2π and 1 minute equals to 60 seconds
180 rpm = 180*2π/60 = 18.85 rad/s
We can use the heat specific equation to find the rate of heat exchange of the steel drill and block:

Since the entire mechanical work is used up in producing heat, we can conclude that the rate of work is also 37.8 J/s, or 37.8 W
The torque T required to drill can be calculated using the work equation



Voltage - V = IR : v= voltage i= current r= resistance
Answer:
In the picture.
Explanation:
I hope that it's a clear solution.