Tag: materials

Quizzes (22) Questions (81)

Questions Related to materials

Multiple choice nanochemistry nanotechnology applied chemistry materials chemistry

Which of the following is true?

  1. The nanomaterials tend to have greater reactivity than the bulk material.

  2. The nanomaterials tend to have lower reactivity than the bulk material.

  3. The nanomaterials tend to have same reactivity as the bulk material.

  4. There is no generalisation between reactivity of nanomaterial and bulk material.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The nanomaterials tend to have greater reactivity than the bulk material. For example, gold nanoparticles are chemically reactive whereas bulk metal is inert.

Multiple choice nanochemistry nanotechnology applied chemistry materials chemistry

Which of the following is true?

  1. The nanomaterials have lower melting points than the bulk material.

  2. The nanomaterials have higher melting points than the bulk material.

  3. The nanomaterials have approximately same melting points as the bulk material.

  4. The nanomaterials can have either lower or higher ( but not equal) melting points than the bulk material.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The nano materials have lower melting points than the bulk material.

Multiple choice nanochemistry nanotechnology applied chemistry materials chemistry

Which of the following is / are true?

  1. When a quantum dot is irradiated with UV light, it emits visible light, the wavelength of which depends on the size of nanoparticles.

  2. The rainbow colours are emitted by the nanoparticles of different size of single substance.

  3. The wavelength of light emitted decreases from red to violet in the rainbow spectrum as the size of the nanoparticles decreases.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All of the given statements are correct.
When a quantum dot is irradiated with UV light, it emits visible light, the wavelength of which depends on the size of nanoparticles. For example, a 3nm cadmium selenide particle emits green light of wavelength 520 nm whereas 5.5 nm particle of the same substance emits red light at the wavelength of 620 nm.
The rainbow colours are emitted by the nanoparticles of different size of single substance.
The wavelength of light emitted decreases from red to violet in the rainbow spectrum as the size of the nanoparticles decreases.

Multiple choice nanochemistry nanotechnology applied chemistry materials chemistry

The size of a nano particle is  about _________ times smaller than the diameter of a single strand of human hair.

  1. 10

  2. 100

  3. 1000

  4. 50000
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The size of a nanoparticle is  about 50000 times smaller than the diameter of a single strand of human hair and 1/100th of a typical bacterium.

Multiple choice nanochemistry nanotechnology applied chemistry materials chemistry

____________ nanotubes are used as strengthening rods and toughening elements in structural composite materials.

  1. Carbon

  2. Gold

  3. Silver

  4. Metal oxide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Carbon nanotubes are used as strengthening rods and toughening elements in structural composite materials. Example of a carbon nanotube is Fullerene nanotube.

Multiple choice nanochemistry nanotechnology applied chemistry materials chemistry

Which of the following lists the disadvantages of nanomaterials?

  1. Nanomaterials are very expensive.

  2. Nanomaterials are also pretty difficult to manufacture.

  3. Nanoparticles are very small, inhalation of these particles can cause problems.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All of the above are the disadvantages of nanomaterials.
Nanomaterials are very expensive.
Also, nanomaterials are also pretty difficult to manufacture
Hence, products made with nanotechnology are more expensive.
Nanoparticles are very small, inhalation of these particles can cause problems similar to the problems from inhaling minute asbestos particles.

Multiple choice nanochemistry nanotechnology applied chemistry materials chemistry

Which of the following lists the disadvantages of nanomaterials?

  1. The value of oil may decrease as more efficient sources of energy might be developed which wont require the use of fossil fuels.

  2. Products at the molecular level can be developed, so that diamonds may lose its value due to mass production.

  3. Both of the above

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The following lists the disadvantages of nanomaterials
The value of oil may decrease as more efficient sources of energy might be developed which won't require the use of fossil fuels.
Products at the molecular level can be developed,  so that diamonds may lose its value due to mass production.

Multiple choice nanochemistry nanotechnology applied chemistry materials chemistry

The nanomaterials are classified into which of the following?

  1. Nanolayers

  2. Nanotubes or nanowires

  3. Nanoparticles

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The nanomaterials are classified into
nanolayers, nanotubes or nanowires and nanoparticles.
Nanolayers are the nanomaterials with only one dimension between 1 nm and 100 nm.
Nanotubes or nanowires are the nanomaterials with two dimension between 1 nm and 100 nm.
Nanoparticles are the nanomaterials with three dimension between 1 nm and 100 nm.

Multiple choice nanochemistry nanotechnology applied chemistry materials chemistry

Gold nanoparticles are highly effective as:

  1. selective oxidation catalysts

  2. selective reduction catalysts

  3. non selective oxidation catalysts

  4. non selective reduction catalysts
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gold nanoparticles are highly effective as selective oxidation catalysts. It is used in the oxidation of alcohols and aldehydes.

Multiple choice nanochemistry nanotechnology applied chemistry materials chemistry

_______ nanoparticles are widely used in sunscreens and cosmetics, stain resistant fabrics and dirt repellent paints.

  1. The metal oxide

  2. Gold

  3. Silver

  4. The metal sulphide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The metal oxide nanoparticles are widely used in sunscreens and cosmetics, stain-resistant fabrics and dirt repellent paints. They are used in sunscreen and cosmetics because they reflect the visible light and absorb UV light efficiently.