Alight with a second-order dark band forms a diffraction angle of 20.0°. the diffraction grating has 200.0 lines per mm. the wavelength of the light, to the nearest whole number, is nm.

the correct answer is 684 nm

684 nm

Explanation:

For n order dark band for diffraction pattern formed by diffraction grating:

d sin θ = (n + 0.5) λ

where, d is the distance between the slits

d = 1/N where N is the number of slits per unit length

θ is angle of diffraction. (θ =20°)

n is integral number ( n =2 for second order)

λ is the wavelength.

d = 1/200 mm = 0.005 mm

⇒λ = (0.005 mm × sin 20°) ÷ (2+0.5) = 684 nm

Thus, the wavelength of light is 684 nm.

explanation:

as the height from which the ruler was dropped increased, the speed of the ruler at ryan's hand increased.

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.