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- Question
The colour of a thin film is due to
Options- A. Scattering
- B. Dispersion
- C. Diffraction
- D. Interference
- Correct Answer
- Interference
ExplanationIn physics, interference is a phenomenon in which two waves superpose to form a resultant wave of greater, lower, or the same amplitude. The color bands in thin films are a result of wavelength dependent interference caused by the close spacing of the surfaces of the film.
- 1. Sound becomes hazardous noise pollution at decibels?
Options- A. above 120 db
- B. above 80 db
- C. above 50 db
- D. above 30 db Discuss
- 2. In a vacuum, all electromagnetic waves have the same
Options- A. Velocity
- B. Wavelenth
- C. Frequency
- D. All the above Discuss
- 3. Resistance of human body in dry condition
Options- A. 10 ohm
- B. 1000 ohm
- C. 10000 ohm
- D. 100000 ohm Discuss
- 4. What causes brownian motion in colloids?
Options- A. coagulation of particles and the dispersed phase
- B. erratic flashes of light
- C. molecules of the dispersion medium colliding with dispersed phase particles
- D. All the above Discuss
- 5. Which of the following has the highest entropy?
Options- A. Hydrogen
- B. Diamond
- C. Liquid nitrogen
- D. Mercury Discuss
- 6. The wavelike properties of electrons are useful in
Options- A. Magnifying objects
- B. Lasers
- C. Weather reports
- D. All of the above Discuss
- 7. Rate at which velocity changes over time?
Options- A. Speed
- B. Displacement
- C. Acceleration
- D. Jerk Discuss
- 8. Electrostatic precipitator is used to control
Options- A. Water pollution
- B. Noise pollution
- C. Air pollution
- D. Solid waste Discuss
- 9. Lux is the SI unit of
Options- A. luminous flux
- B. luminous efficiency
- C. intensity of illumination
- D. luminous intensity Discuss
- 10. Earlist thermometerr was developed by
Options- A. Celsius
- B. Fahrenheit
- C. Kelvin
- D. Galileo Discuss
Physics problems
Search Results
Correct Answer: above 120 db
Explanation:
Sound intensity is measured in decibels(db). Sound pollution above 120 db becomes more hazardous and have adverse affects on human life.
Correct Answer: Velocity
Explanation:
When traveling in a vacuum, electronic waves from the electromagnetic spectrum all travel at the same speed. Velocity is speed with direction, so they would all travel at the same velocity, realtively speaking. But frequency and wavelength are quite different.
Correct Answer: 100000 ohm
Explanation:
Under dry conditions, the resistance offered by the human body may be as high as 100,000(10^5) Ohms.
Depending on the person, a rough value for the internal resistance of the human body is 300-1,000 Ohms. The skin's resistance is much lower if it is wet or burnt/blistered.
There are a lot of factors involved and not every person has the same electrical resistance. For instance, men tend to have lower resistance than women.
Within the body, the tissues with the greatest resistance are bone and fat - nerves and muscle have the least resistance.
Correct Answer: molecules of the dispersion medium colliding with dispersed phase particles
Explanation:
When their is a colloid in the solution, then it will show the Brownian movement, such as dust particle in the air will show the Brownian movement.
Hence, Brownian movement arises due to the impact of the molecules of the dispersion medium with the colloidal particles. It has been postulated that the impact of the molecules of dispersion medium on the colloidal particles are unequal.
This leads to the zig-zag (random) motion of the colloidal particles.
Correct Answer: Hydrogen
Explanation:
Entropy is a measure of disorder . It will be maximum in gases followed by liquids and least in solids.
Hence, here the gas is only hydrogen and it has the highest entropy.
Correct Answer: Magnifying objects
Explanation:
The photoelectric effect pointed to the particle properties of light, which had been considered to be a wave phenomenon. Particles like electron and protons have both particle like and wave like behavior. Thus, according to de Broglie, all the material particles in motion possess wave characteristics. Although the dual nature of matter is applicable to all material objects but it is significant for microscopic bodies only.
Correct Answer: Acceleration
Explanation:
Acceleration is nothing but the rate at which velocity changes over time.
Correct Answer: Air pollution
Correct Answer: intensity of illumination
Explanation:
The lux (lx) is the SI derived unit of illuminance and luminous emittance, measuring luminous flux per unit area. It is equal to one lumen per square meter.
Correct Answer: Galileo
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