BS Bachelor of Science: Life, Physical, and Chemical 3 — Questions and Answers
Question 1: According to Newton's second law of motion, if a net force of 20 N acts on a 4 kg object, what is its acceleration?
- 80 m/s²
- 0.2 m/s²
- 5 m/s² (Correct answer)
- 16 m/s²
Correct answer: 5 m/s²
F = ma, so a = F/m = 20 N / 4 kg = 5 m/s².
Question 2: Which type of electromagnetic radiation has the shortest wavelength?
- Radio waves
- Visible light
- X-rays
- Gamma rays (Correct answer)
Correct answer: Gamma rays
Gamma rays have the shortest wavelength (and highest frequency and energy) in the electromagnetic spectrum.
Question 3: A wave transfers energy from one place to another without transferring matter. Which property describes the number of wave cycles that pass a point per second?
- Wavelength
- Amplitude
- Frequency (Correct answer)
- Speed
Correct answer: Frequency
Frequency, measured in hertz (Hz), is the number of complete wave cycles that pass a given point per second.
Question 4: Which law states that the total momentum of a closed system remains constant if no external forces act on it?
- Law of universal gravitation
- Conservation of momentum (Correct answer)
- Ohm's law
- Boyle's law
Correct answer: Conservation of momentum
Conservation of momentum states that total momentum of an isolated system remains constant.
Question 5: In a simple electric circuit, if resistance doubles while voltage remains constant, what happens to the current?
- Doubles
- Stays the same
- Quadruples
- Halves (Correct answer)
Correct answer: Halves
By Ohm's law (I = V/R), doubling R while keeping V constant cuts current in half.
Question 6: Which phenomenon explains why a straw appears bent when placed in a glass of water?
- Reflection
- Diffraction
- Refraction (Correct answer)
- Interference
Correct answer: Refraction
Refraction is the bending of light as it passes from one medium (water) into another (air) of different optical density.
Question 7: The half-life of a radioactive isotope is 10 years. After 30 years, what fraction of the original sample remains?
- 1/2
- 1/4
- 1/8 (Correct answer)
- 1/16
Correct answer: 1/8
After three half-lives (30 years), (1/2)³ = 1/8 of the original sample remains.
BS Bachelor of Science: Life, Physical, and Chemical 3
According to Newton's second law of motion, if a net force of 20 N acts on a 4 kg object, what is its acceleration?