1) Consider light with a wavelength of 580 nm incident on a diffraction grating

Question

1) Consider light with a wavelength of 580 nm incident on a diffraction grating with 460 lines per mm. What is the highest order bright fringe possible for this situation?

A. 1st

B. 2nd

C. 3rd

D. 4th

E. None of the above. There is no limit the number of fringes that can be observed.

2)

Let M be the magnification. What best describes the image formed by the eyepiece lens?
A. Virtual and M < 1
B. Real and M < 1
C. Virtual and M > 1
D. Real and M > 1
E. Virtual and M = 1

In al refracting telescope two convex lenses are used to generate an enlarged image of a distant object (see Figure1). The light from the object first enters the objective lens which will produce a real image, l1. This image then acts as the object for the second lens, the eyepiece. The image formed by the eyepiece lens, 12, is the image seen by the user of the telescope. Objective lens Eyepiece lens ligure 1

Explanation / Answer

1) C. 3rd

2) c. Virtual and M>1

For the objective lens, the image is formed by the actual meeting of the rays, so it is real.As we can see, it is smaller than the object so the magnification M is <1.

(Image formed by actual ray meeting is real and formed by the rays appearing to mee, i.e. after extending the rays, is virtual.

If image is larger than the object, M>1 and if it is smaller then M<1)

Image of objective is the object for the eyepiece. As can be seen, the image is formed by the rays appearing to meet and is larger than the object.

So the image is virtual and M>1

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.