# VJC

Popular questions and responses by VJC
1. ## physics

An electron starting from rest acquires 4.20 keV of kinetic energy in moving from point A to point B. How much kinetic energy would a proton acquire, starting from rest at B and moving to point A? Determine the ratio of their speeds at the end of their

2. ## College Physics II

A typical gamma ray emitted from a nucleus during radioactive decay may have an energy of 736 keV. What is its wavelength? A microwave oven produces electromagnetic radiation at λ = 12.1 cm and produces a power of 778 W. Calculate the number of microwave

3. ## physics

On planet Tehar, the acceleration of gravity is the same as that on Earth but there is also a strong downward electric field with the field being uniform close to the planet's surface. A 2.16 kg ball having a charge of 4.80 uC is thrown upward at a speed

4. ## College Physics II

1) An electron moving with a speed of 2.84E+6 m/s has the same momentum as a photon. Calculate the de Broglie wavelength of the electron. 2) Calculate the wavelength of the photon.

5. ## physics

A high-voltage power line carries a current of 120 A at a location where the Earth's magnetic field has a magnitude of 0.577 G and points to the north, 70.8° below the horizontal. Calculate the magnitude of the magnetic force exerted on a 258 m length of

6. ## Physics

Suppose a spacecraft of rest mass 34000 kg is accelerated to 0.206c. How much kinetic energy would it have? If you used the classical formula for KE, by what percentage would you be in error? Do not enter units.

7. ## Physics

Calculate the magnitude of the electric field at the center of a square with sides 22.4 cm long if the corners, taken in rotation, have charges of 1.02 μC, 2.04 μC, 3.06 μC, and 4.08 μC (all positive).

8. ## College Physics II

What is the longest wavelength light capable of ionizing a hydrogen atom in the n = 4 state? i know that Solve h c/L = (Rydberg)/6^2 for L something along those lines... but what am i solving for and what is c and h?

9. ## physics

How much work is needed to move a proton from a point with a potential of +470 V to a point where it is -51.0 V? Express your answer in joules. Express your answer in electron volts.

10. ## physics

A 5.30 cm diameter wire coil is initially oriented so that its plane is perpendicular to a magnetic field of 0.570 T pointing up. During the course of 0.190 s, the field is changed to one of 0.350 T pointing down. What is the average induced emf in the

11. ## physics

The force on a wire is a maximum of 7.33E-2 N when placed between the pole faces of a magnet. The current flows horizontally to the right and the magnetic field is vertical. The wire is observed to "jump" toward the observer when the current is turned on.

12. ## physics

An emf is induced in a conducting loop of wire 1.24 m long as its shape is changed from square to circular. Calculate the average magnitude of the induced emf if the change in shape occurs in 4.21 s, and the local 0.123 T magnetic field is perpendicular to

13. ## physics

An electric field of 630 V/m is desired between two parallel plates 15.9 mm apart. How large a voltage should be applied?

14. ## physics

A 34.7 cm diameter coil consists of 20 turns of circular copper wire 1.50 mm in diameter. A uniform magnetic field, perpendicular to the plane of the coil, changes at a rate of 9.00E-3 T/s. Determine the current in the loop. Determine the rate at which

15. ## Physics

At a certain location, the Earth's magnetic field has a magnitude of 5.90E-5 T and points in a direction that is 71.6° below the horizontal. Calculate the magnitude of the magnetic flux through the top of a desk at this location that measures 132 cm by

16. ## Physics

What is the speed of a 680 eV electron? What is the speed of a 3.50 keV electron?

17. ## physics

A proton with a kinetic energy of 5.00E-16 J moves perpendicular to a magnetic field of 0.289 T. What is the radius of its circular path?

18. ## physics

Two parallel plates, separated by 10 mm, are charged to a potential difference of 50 V (that is, one plate is 0 V and the other plate is 50 V). Which of the following statements are true? the electric potential at the midpoint between the plates is 50 V

19. ## physics

An object has a total energy that is two times its rest energy. What is its speed? Give answer in c. what equation do i use to solve this? step by step anyone?

20. ## College Physics II

A uniform electric field of magnitude 203 V/m is directed in the negative y direction. A +12.5 μC charge moves from the origin to the point (x, y) = (19.5 cm, 51.8 cm). 1) What was the change in the potential energy of this charge? 2) Through what

21. ## Physics

A uniform electric field of magnitude 203 V/m is directed in the negative y direction. A +12.5 μC charge moves from the origin to the point (x, y) = (19.5 cm, 51.8 cm). 1) What was the change in the potential energy of this charge? 2) Through what

22. ## Physics

A 17.0 cm diameter circular loop of wire is in a 1.35 T magnetic field. It is removed from the field in 0.190 s. What is the average induced emf?

23. ## College Physics II

Consider a region in space where a uniform electric field E = 7450 N/C points in the negative x direction. What is the distance between the +13.1 V and the +14.1 V equipotentials?

24. ## College Physics II

A charge of -4.191 μC is located at (5.100 m, 6.402 m), and a charge of 1.895 μC is located at (-1.436 m, 0). Calculate the electric potential at the origin There is one point on the line connecting these two charges where the potential is zero. What is

25. ## College Physics II

If a capacitor has 3.84 μC of charge on it and an electric field of 2.22 kV/mm is desired if they are separated by 3.80 mm of air, what must each plate's area be?

26. ## physics

Protons move in a circle of radius 4.10 cm in a 0.570 T magnetic field. What value of electric field could make their paths straight?

27. ## College Physics II

What is the de Broglie wavelength of electrons with the following value of kinetic energy? 1.06 eV; What is the de Broglie wavelength of electrons with the following value of kinetic energy? 1.06 keV.

1. ## College Physics II

so i would do speed of light/(rydberg)/6^2=h?

posted on December 8, 2010
2. ## Atomic physics

what is h and c?

posted on December 8, 2010
3. ## Physics

what would happen if it became 1/4 the total energy instead? how would the equation be set up?

posted on November 17, 2010
4. ## physics

what is H?

posted on September 15, 2010