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  1. YMMMA

    Confused about the number of absorption lines

    Homework Statement If an atom in energy level 1, how many absorption spectral lines can an atom exhibit due to transition between 3 levels? How about 4 and 5 levels? And also in emission? Homework Equations Concept The Attempt at a Solution I am confused one book says it can absorb a photon...
  2. YMMMA

    What is the magnitude of acceleration?

    Homework Statement Objects X and Y, shown below, are released fronm rest in outer space. The only force acting on the objects is their mutual gravitational attraction. The mass of X is one-half that of Y. With respect to the original rest frame, the magnitude of the acceleration of X is (A)...
  3. YMMMA

    What are the frequency and speed of a photon after scattering

    Homework Statement Photons incident upon free electrons that are essen- tially at rest are scattered by the electrons. As a consequence, the electrons gain kinetic energy. How do the frequency and speed of the photons present after the scattering compare to those present before the scattering...
  4. YMMMA

    Which graph represents the Energy of a photon vs intensity?

    Homework Statement If X represents the intensity of monochromatic blue light and Y represents the energy of each photon of the light, which one is the correct graph below? Homework Equations KE=hƒ-∅, where ∅ is the work function Energy of a photon= hƒ The Attempt at a Solution Increasing the...
  5. YMMMA

    Elliptical orbit/ determine speed & potential energy

    Homework Statement True statements about Jupiter as it moves in its elliptical orbit around the Sun include which o the following? I. It has its greatest speed when closest to the Sun. II. It has its greatest potential energy when farthest from the Sun. III. The magnitude of its...
  6. YMMMA

    Path length differences/ interference problem

    Homework Statement In the figure below, Two wave sources, M and N, are vibrating in phase on the surface of water and generate waves of wavelength λ. Which of the following values for the distances MP and NP will result in minimum disturbance at a particular point P on the surface of the water...
  7. YMMMA

    Circular motion/ speed increases at a constant rate

    Homework Statement If an object moves in a circular path with a speed that increases at a constant rate, which of the following can be concluded? (A) The radial component of the force acting on the object is zero. (B) The net force acting on the object is zero. (C) The net force acting on...
  8. YMMMA

    Why the large ball falls farther than the smaller one?

    Homework Statement A large and a small ball, made of the same uniform density foam, are released at the same time from a point 100 meters above Earth. After 1 second the large ball is observed to have fallen farther than the small ball. Which of the following explains this observation? (A)...
  9. YMMMA

    Describe what happens to a box attached to a pulley + spring

    Homework Statement The figure below shows a block attached to a pulley and a string. 1) which quantity has essentially the same nonzero value at all three points? 2) which quantity changes direction at point Z? 3)which quantity is zero at point Y? Homework Equations Restoring force = -kx...
  10. YMMMA

    What happens as a gas expands?

    Homework Statement In the figure below, the volume expands while the pressure is constant. What happens when this gas expands? A) heat is added and temperature increased B) heat is removed and temperature decreasesd C) heat is added and temperature decreased D) heat is removed and temperature...
  11. YMMMA

    What causes electric field/ magnetic field?

    Homework Statement What causes electric field? What causes magnetic field? (I) stationary electric fields (II) moving electric charges (III) a changing magnetic field IV) a current-carrying wire Homework Equations E=F/q B=μI/2πr E electric field F elecric force Q charge B magnetic field I...
  12. YMMMA

    PV diagram/ which labeled process has no temperature?

    Homework Statement I have had a question in my quiz that I don’t remember very well, but here’s a diagram and there’s no need for numbers in axis because it’s a concept- based question with no calculations. The question asks if an ideal gas system moved from A-B-C-A. Where is the process by...
  13. YMMMA

    Determine the distance the object travels

    Δ1. Homework Statement Below Homework Equations [/B]Potential energy = kinetic energy MgΔY=1/2 mΔv^2 Vf^2=Vi^2+2gx1 The Attempt at a Solution For question 49, I used the first equation, and the result is Δv^2=2gY. Then, solving for x1 in the second equation, I got x1=Δv^2 / 2g...
  14. YMMMA

    Calculate the average speed

    Homework Statement In the file below. Homework Equations Speed= total distance over total time. Acceleration = change of speed over time The Attempt at a Solution [/B] I tought it is just E because of the first rule above. But then I doubt my answer since it moved with constant acceleration...
  15. YMMMA

    Calculate the wavelength when electron transits.

    Homework Statement A photon of wavelength 300nm is emitted from an atom when an electron makes a transition from an energy state of -4 eV to a state of -8 eV. IF the initial state had been at enerygy of -6 eV, the wavelength of the photon emitted in a transition to -8eV is..?? Homework...
  16. YMMMA

    What would happen to the charge and capacitance?

    Homework Statement In the attached file.. The question asks about the charge and capacitance after being separated by twice the original separation. I also need to know if it is kept connected to the battery( spearted to twice the distance,too) , what would happen to both the charge and...
  17. YMMMA

    How far will the girl run before catching the ball?

    Homework Statement Below Homework Equations Y=1/2 *gt^2 X=Vt Vf=Vi+gt The Attempt at a Solution The ball will have the same final velocity as Its initial. So, using the last equation 0=5+gt, where g is 10. Therefore, time to reach the maximum height is half seconds. To reach the same height it...
  18. YMMMA

    What is the direction of the velocity/ elastic collisions.

    Homework Statement in the attached file Homework Equations Momemtum = mass - velocity The Attempt at a Solution I solved it E. Since object 2 has the larger mass, the effect is less and will move backwards a little bit.
  19. YMMMA

    Potential energy of a block moving up and down an incline.

    Homework Statement Which graphy represents the potential energy of the block as a function of time? Homework Equations PE=mgh The Attempt at a Solution First, the potential energy is zero until it reache the top of the incline where the potential energy is maximum. Moving down, the potential...
  20. YMMMA

    What are the forces acting on an object?

    Homework Statement In the attached file file. Homework Equations None The Attempt at a Solution In both cases Earth’s gravitational force always acts. For the sled, there is a force opposing the motion which can both be the frictional force between the sled and the hill and air resistance...
  21. YMMMA

    Where is the electric field greatest in magnitude?

    Homework Statement In the file Homework Equations No equations needed The Attempt at a Solution I answered it C. Since I learned that at the tip there are most of the charges. Therefore, it’s the point of the greatest E field magnitude. But another tutor told me that it is a circle, and...
  22. YMMMA

    Magnetic force direction on a positive and negative charges

    Homework Statement The question askes about the path of the electron. I need to know if I am doing it correctly whether it was asked for a proton or an electron. Homework Equations F=QV⊥Bsinθ The Attempt at a Solution I answered it C. Because it is an electron, I used my left hand. My thumb...
  23. YMMMA

    Electricity: 2 charged rods connected to a voltage source

    Homework Statement In addition to the question given in the attached file below, I don’t understand how is the polarity changing periodically. Homework Equations Concept-based question, I guess. The Attempt at a Solution I have no idea how should I approach the question. So, if anyone has an...
  24. YMMMA

    Compare the speed and frequency of a wave in a thick rope

    Homework Statement In the attached file. Homework Equations No equations needed. The Attempt at a Solution I answered it B. Not sure,though. If it is a thick rope the frequency decreses; therefore, the speed decreases.
  25. YMMMA

    Physics: Circular motion and the orbital speeds of satellites

    Homework Statement Satellite 1 has mass m1 & radius R1 and satellite 2 has mass m2 and radius 2R1 Which satellite’s speed is greater? Question and my attempt are shown in the attached file. Homework Equations V= √GM/R The Attempt at a Solution I am not sure if my steps are correct, but if...
  26. YMMMA

    Physics: vertical motion and velocity/kinematics

    Homework Statement In the attached file Homework Equations Kinematics equations. The Attempt at a Solution The question asks about vertical component. Isn’t this always 0? Like in C the intial velocity is the horizontal velocity but the vertical one is 0. Same applies to all. Am I correct?
  27. YMMMA

    Physics: transverse wave & wavelength & motion

    Homework Statement the question asks at which point is the string moving upward at the instant shown? Homework Equations No equations needed The Attempt at a Solution I am not sure how I should approach this type of questions. A) will move downward B) downward then upward C) upward then...
  28. YMMMA

    Physics: wavelength of sound waves

    Homework Statement Stated in the attached file. Homework Equations Wavelength = 2 times length divided by harmonic I don’t know if it’s the relevant equation The Attempt at a Solution I used the equation I wrote. So, if the left side is 10cm longer, I guess it might be 2(10).
  29. YMMMA

    Physics: Projectile motion -- Maximize the distance and hang-time of a soccer ball

    Homework Statement The question is in the pic. Homework Equations The Attempt at a Solution I answered it B. Still i am not quite sure whether it is B or E. I assumed some numbers, though.
  30. YMMMA

    Physics question: index of refraction

    Homework Statement [/B] In order for the refracted ray R to have the same direction in space as the incident ray I, shown above, which of the following conditions by itself would be sufficient? (A) n1=n2 (B) n1=n3 (C) n2=n3 (D) Plane surface P, is parallel to plane surface P2- (E) None of the...