Electrons in excited hydrogen atoms are in the

n = 3 energy level. How many different photon

frequencies could be emitted as the atoms return

to the ground state?

(1) 1 (3) 3

(2) 2 (4) 4

A bike first accelerates from 0.0 m/s to 5.0 m/s in 4.5s, then continues at this constant speed for another 4.5 s. What is the total distance traveled by the bike?

Julie has decided to manage her weight and has asked her friends for advice. Which of the following statements shows how Julie's friends could be a positive influence? "You definitely look like you need to lose weight.

A traveling electromagnetic wave in a vacuum has an electric field amplitude of 71.1 V/m. Calculate the intensity S of this wave. Then, determine the amount of energy U that flows through area of 0.0275 m 2 over an interval of 16.

A softball player hits a ball at 29.5 m/s at a 33.0° angle. An outfielder catches the ball at the same height. How far was the outfielder from the hitter?

One astronomer believes that the density of the universe remains constant. One physicist believes that the density of the universe changes over a period of time.

2. How is temperature related to kinetic energy?

As stream velocity decrease, which factor will likely increase? A) erosion of the stream bank B) deposition of material in the stream C) amount of material carried downstream D) size of the particles carried downstream

What cells in the nervous signals travel through the nervous system

A mechanic pushes a 3.60 ✕ 103-kg car from rest to a speed of v, doing 5,130 j of work in the process. during this time, the car moves 21.0 m. neglecting friction between car and road, find v and the horizontal force exerted on the car.

Anika asks Eva to roll a basketball and then a bowling ball to her. Which requires more force to roll, and why?