81. What are the wavelengths of (a)X-rays of frequency 2.0times 10^17 Hz? (b)Yellow light of frequency 5.1times 10^14 Hz? (c) Gamma rays of frequency 1.0times 10^23

Which of the following statements are true? Check all that apply. A hydrogen atom in the n=4 state is at a lower energy than one in the n=3 state. A hydrogen atom in the n=3 state can emit light at only two specific wavelengths. The energy of an emitted photon equals the energy difference of the two states involved in the emission.

The Earth's blue sky color is due to a. Reflections of blue light by the atmosphere b. Absorption of all visible light by the atmosphere c. Ocean colors

A projectile is launched from ground level at 10^circ above the horizontal and lands downrange. What other projection angle (in degrees)for the same speed would produce the same down-range distance?

Nuclear __ is a reaction in which two or more atomic nuclei are combined to form one or more different atomic mucleus and subatcmic particles (neutrons or protons) a. fusion b. fission

The opening and closing of the lid of your jar of peanut butter uses the technique of a __ pulley screw wedge wheel and axle

Which statement describes the heliocentric theory, as stated by Copernicus? The moon was at the center of the universe. The stars were at the center of the universe. The Earth was at the center of the universe. The Sun was at the center of the universe.

Acar initially moving at a speed of 5.0m/s accelerates at a rate of 3.0m/s for 8.0 seconds. What final speed does the car reach? 35.0m/s 29.0m/s 25.0m/s 31.0m/s Clear my selection

Which of these planets is known to be without an atmosphere? Mercury Earth Venus Mars

The change in internal energy is always equal to the heat exchanged at constant pressure. False True

Hot Questions

A heavy stone and a light stone are released from rest in such a way that they both have the same amount of gravitational potential energy just as they are released. Air resistance is negligibly small Which of the following statements about these stones are correct? (There could be more than one correct choice.) a) The stones must have been released from the same height. b) Just as it reaches the ground, the light stone is traveling faster than the heavy stone. c) The initial height of the light stone is greater than the initial height of the heavy stone. d) The stones both have the same speed just as they reach the ground. e) The stones both have the same kinetic energy just as they reach the ground.

33. What does a transformer do? 34. Write the transformer equation relating voltage and number of turns. 35. A transformer has 200 turns in the primary coil and 20 in the secondary coil If the input voltage is 2400 V.what is the output voltage? 36. Why is voltage stepped up for power transmission over long distances?

Calculate the force on a 160m wire carrying 150A of current if a magnetic field of $5\times 10^{-5}$ T makes a $165^{\circ }$ angle with the wire. $\square $ N

Two iron bars attract each other no matter which ends are placed together. Are they both magnets? Explain. $\square $

Absolute vorticity is a combination of curvature and shear vorticity. True False

A gravitational field surrounds anything that has __ A density B electricity C velocity D mass

You would have the largest mass of gold if it weighed 1 N on the Moon Earth both the same on the Earth the mass will be double

How many significant figures are in this length? .002500 dm $\square $

A projectile travels 1,120 feet per second. How fast is the projectile traveling in miles per hour? The projectile travels $\square $ miles per hour. (Type an integer or decimal rounded to the nearest tenth as needed )

Use the formula $F=G\frac {m_{1}m_{2}}{d^{2}}$ where $F=the\quad force\quad of\quad gravity$ $G=universal\quad gravitational\quad constant$ $m_{1}$ and $m_{2}=masses\quad of\quad the\quad two\quad objects$ $d=the\quad distance\quad between\quad the\quad centers\quad of\quad the\quad two\quad objects$ What would result in the greatest gravitational force between two objects? A halving the mass of object 1 B doubling the mass of object 1 C halving the distance between the two objects D doubling the distance between the two objects