Can someone help me with physics hw

Question

1) a microwave has a typical wavelength of about 0.1 meter. What us the comparable wavelength of a radio wave?

A) less than 0.1 meter

B) greater than 0.1 meter

C) equal to 0.1 meter

D) it depends on the frequency

2) the speed of a light wave C is related to its wavelength λ and its frequency f by C=λf. If the speed of light is 3 × 10^8 meters/second and the wavelength of an infrared wave used in a remote control is 7 × 10^-9 meters, then what is its frequency?

a) 4 × 10^-2 Hz

B) 2 × 10^-17 Hz

C) 4 × 10^16 Hz

D) 2 × 10^0 Hz

3) the probability that a randomly chosen nucleus in a radioactive sample will behave decayed in a given time Is 96.875%. How many half-lives has the sample experienced?

A) 6

B) 3

C) 5

D) 4

4) a radioactive sample starts with 800,000 undecayed nuclei. After 12 hours, 700,000 of the nuclei have decayed. What is the half life of the sample?

A) 4 hours

B) 12 hours

C) 3 hours

D) 6 hours

5) the half-life of radium-226 is 1,600 years and the half life of carbon-14 is 5,730 years. Mathematically prove that the decay constant for radium-226 is larger than the decay constant for carbon-14

6) how does the photoelectric effect support a particle model of electromagnetic radiation? evaluate the idea that radiation frequency and intensity highlight how the wave model is inadequate to explain the photoelectric effect

7) how did the development of electrical signals sent through wires change communication?

A) signals could be sent anywhere a wire could reach and no longer were restricted to line of sight

B) signals were amplified with distance

C) signals no longer attenuated with distance

D) the electrical signals were more accurate than optical semaphore signals

8) source A has a half-life of 10 million years, and source B has a half-life of 5 million years. After 10 million years, what percent of each source remains?

A) 25% of source A and 0% of source B

B) 50% of source A and 25% of source B

C) 50% of source A and 0% of source B

D) 25% of source A and 25% of source B

9) which statement is correct about the half-lives of radioactive elements?

A) the half-lives of radioactive elements vary within a similar range of a few seconds

B) the half-lives of radioactive elements with more neutrons become larger

C) the half-lives of radioactive elements vary from fractions of a second to billions of years

D) the half-lives of radioactive elements with more neutrons become smaller

Answer 1

Sarah, while I *can* answer these for you I will not. This homework is straight forward for this topic. If you find these difficult to answer after reading the textbook and demonstration by the instructor, you should find a tutor.

Best,

Charles