37. Give two examples of different fossil fuels currently used today?

38.Explain how voice is changed into a fluctuating voltage in the early telephones?

39. What 1799 discovery allowed us to translate the ancient Egyptian hieroglyphs?

40.In the scientific method or process an explanation about natural phenomena with little or no experimental fact is called a ________________.

A diffraction grating has 25,000 lines/cm and is illuminated with light having a frequency of 5.0 x 10​14​ Hz. What are the angles of (a) the first-order bright fringe and (b) the second-order bright fringe?

An engineering students designs and builds a capacitor from some scrap iron. One piece of iron is a square with side lengths of 10 cm, while the other piece is a rectangle that is 20 cm long and 10 cm wide. The student knows they can keep the plates separated by a distance of 1.2 micrometers.

a. What is the capacitance of this setup?

b. If the capacitor is fully charged using a 1.5 V battery, how much charge is built up on the plates?

c. How much energy is stored?

d. After performing the experiment, the student inserts a dielectric with a k value of 1.2. What values would this change?

A disk-shaped merry-go-round of radius 2.63 m and mass 155 kg rotates freely with an angular speed of 0.570 rev/s. A 59.4-kg person running tangential to the rim of the merry-go-round at 3.82 m/s jumps onto its rim and holds on. Before jumping on the merry-go-round, the person was moving in the same direction as the merry-go-round's rim.

(a) Does the kinetic energy of the system increase, decrease, or stay the same when the person jumps on the merry-go-round?

(b) Calculate the initial and final kinetic energies for this system.

A space station consists of three modules, connected to form an equilateral triangle of side length 82.0 m. Suppose 100 people, with an average mass of 75.0 kg each, live in each capsule and the mass of the modules is negligible compared to the mass of the people. If everyone went to the top left module for a parade what would be the change in position of (a) the center of mass of the station and (b) top left module, during the parade (Assume the actual station's mass is negligible)? Suppose now that everyone is back to their respective module and artificial gravity is simulated by rotating the station. (c) How fast would one of the modules have to be moving to simulate gravity on earth? (d) If the station does not change mass or interact with an outside agent, could it actually go from a state of not rotating to a state of rotating? Explain. Suppose that the station is rotating at the artificial Earth gravity speed and the moment of inertia of the station without the people is 2.00x109 kg·m2.If the distance between each module is reduced to half, what will be the new (e) tangential velocity and (f) radial acceleration in units of g?

Discuss stress and strain of materials in terms of Hooke's law. Please be detailed.

explain how to prepare sample solutions and capillary applicators

Answer the following questions involving specific heat capacities :

a ) How much energy is required to change 42 g ice cube from ice at -11°C to steam at 111°C?

b ) Liquid nitrogen, which has a boiling point of 77 K, is commonly used to cool substances to low temperatures. How much energy must be removed from 1.0 kg of gaseous nitrogen at 77 K for it to completely liquefy?

c ) How much energy is needed to melt 0.225 kg of lead so that it can be used to make a lead sinker for fishing? The sample has an initial temperature of 27.3°C and is poured in the mold immediately after it has melted.

A certain red giant star has a luminosity of 100,000 times that of the Sun and is located 600 light-years from Earth. If the apparent magnitude of the star is observed to be m=0, calculate the rate of interstellar extinction in the direction of the star.

If someone could show me step by step how to solve this I would be appreciative.

A man drops a rock into a well.

(a) The man hears the sound of the splash 2.20 s after he releases the rock from rest. The speed of sound in air (at the ambient temperature) is 336 m/s. How far below the top of the well is the surface of the water? (answer in meters)

(b) If the travel time for the sound is ignored, what percentage error is introduced when the depth of the well is calculated? (percentage)

Consider the following AC circuit. Let R = 1.0kΩ, C = 150µF and L = 10.0 mH. The AC voltage source is of frequency 60 HZ and has a maximum voltage Vmax of 100 V. Find a) the capacitive reactance, b) inductive reactance, c) total impedance, d) RMS current, e) voltage drop across the inductor, f) voltage drop across the capacitor, g) phase angle, h) draw the phasor diagram for all voltage drops and the resulting phasor, and i) is the circuit capacitive of inductive?

a. For point charge 5.4 µC and point charge -3.6 µC located at the same positions as in the previous question (5 m and 4 m, respectively), determine the magnitude of the net electric field E at the origin (in N/C).

Your answer should be a number with two decimal places, do not include the unit.

b. For point charge -1.4 µC and point charge 5.8 µC located at the same positions as in the previous question (5 m and 4 m, respectively), determine the direction of the net electric field E at the origin.

1µC = 10-6C

Your answer should be an integer, do not include the unit.

An infinitely long, solid non-conducting rod (cylinder) with circular cross section of radius a has its axis along the z-axis. It has a non-uniform volume charge density given in cylindrical coordinates by ρ(s) = C (s/a)^2 ,where C is a positive constant. In addition, there is a uniform volume charge density −σ on the outer cylindrical shell of radius b, where σ is a positive constant. Region 2 is a vacuum.

For parts (a) through (c), use Gauss’ Law and determine the electric fields (both magnitude and direction of the electric field) in

(a) Region 1: inside the inner cylinder (s < a)

(b) Region 2: between the inner and outer cylinders (a < s < b)

(c) Region 3: outside the outer cylinder (s > b)

(d) Is the electric field continuous at each surface? (s = a and s = b surfaces)

(e) What is the electric potential difference ∆Vab between the surface of the inner cylinder (s = a) and the surface of the outer cylinder (s = b)? Which surface has a higher potential? 1.

2) We can model the earth as a solid spherical conductor of radius RE surrounded by a concentric spherical conducting shell with inner radius Ri , and outer radius Ro, which is the ionosphere. The earth has charge +Q, while the ionosphere has zero net charge.

Write all answers in terms of Q, RE, Ri , Ro, and 0.

For parts (a) through (c), what is the surface charge density on

(a) the outer surface of the inner sphere of radius RE?

(b) the inner surface on the spherical shell at radius Ri?

(c) the outer surface of the spherical shell at radius Ro?

For parts (d) through (g), determine the electric field E(r) everywhere in space:

(d) r < RE

(e) RE < r < Ri

(f) Ri < r < Ro

(g) r > Ro

(h) Calculate the energy of the system.

(i) Determine the potential at the center given that the potential is zero at r = ∞.

(j) Find the capacitance of the earth-ionosphere system assuming that the ionosphere has net charge −Q instead of zero.

3) Two charges are on the z-axis, charge +q at z = +a and −q at z = −a. (Hint: This is NOT a continuous charge distribution but two discrete point charges.)

(a) Find the electric potential V (x, y, z) at a field point r = (x, y, z).

(b) Find the potential V (x, y, 0) at a point (x, y, 0) on the xy-plane.

(c) What is the total electrostatic energy of this system?

(d) Using the result of part (c), find out how much work it takes to move the charges closer so that their separation is a rather than 2a.

An archeological specimen containing 9.42 g of carbon has an activity of 1.58 Bq. How old (in years) is the specimen? Do not enter unit.

Givens (Questions 1