# Physics

## 14. Light with a wavelength of 646 nm passes through two slits and forms an interference pattern on a screen 8.75 m away. The distance between the central bright fringe and the second-order bright fringe is 5.16 cm. What will be the distance between the central bright fringe and the third-order minimum! A) 0.13 m B) 0.18 m C) 0.24 m D) 0.34 m E) 0.47 m

EXPERT ANSWER According to question, light has wavelength,  = 646 nm = 646 * 10-9 m. distance of screen from slits, D = 8.75 m Distance between central bright fringe and second order bright fringe is, y = 5.16 cm = 5.16 * 10-2 m. i.e for n = 2 Since, for maxima Where d is distance between …

## i. Project Fili: an X-ray telescope (λ≈0.1−1 nm) in Antarctica for studying black holes. ii. Project Kili: a visible-light telescope (λ≈400−700 nm) in Hawai’i for studying galaxy formation.

Imagine that you are in charge of allocating funding from the national science foundations to build one or more proposed observations. For each of the pair below determine which one would be better to fund and clearly explain your reasoning. EXPERT ANSWER Its better to fund the project kili. Project Kili involves setting up a visible …

## Change the mass of each of the blocks seven times.

1. Change the mass of each of the blocks seven times.2. Record your data on the Data Table.3. For each combination of the mass change the coefficient of frictionbetween the block and the table three times.4. Record your data on the Data Table.5. Consider the block being pulled horizontally at a constant velocity. Derivethe equation …

## 3. The figure below shows the equipotential lines created by a distribution of source charges (not pictured here) along with five locations in space (a-e). a. At each of the points indicated, draw the electric field vector (magnitude and direction) b. An ion is placed, initially at rest at point c and allowed to move solely due to the electric force. At a later time, the ion is at point b. Is the ion positively or negatively charged? What is that ion’s speed at point b? Explain your reasoning c. At what location on the figure is the ion traveling the fastest? Explain. d. If instead, you doubled the charge on the ion: how does the lon’s speed at point b change from your previous answer? how does the fastest speed of the ion change from the previous case? (be as numerical as possible, e.g., “double) e. A different charged object gains 5 J of kinetic energy as it moves from point b to a What is its charge (and make sure to include if it is positive or negative)? f. When an electron is located at point d, it has velocity vo to the right. The electron reaches pointe before it turns 300 V 100 V around. At a later 1200 V time, the electron’s velocity is 2v, to the 1 lllclla left. At what location on the figure is the IIII!! electron located 250 v when this happens? 250 V Is there more than one answer? 300 V 200 V le 50V 350 v 156 v

EXPERT ANSWER (a). The strength of the field is shown by the no. Of field lines around that point. Maximum electric field is at point c.