GSEB Solutions for Class 10 Science and Technology – An Introduction to Nanotechnology (English Medium)
Select the proper choice from the given multipule choices :
10 nanometer =……….. meter
A. 10-8 m
One nanometer is equal to 10-9 m. Hence, 10 nanometer is equal to 10 × 10-9 = 10-8 m.
Size of nanoparticles range between……………
C. 1 to 100 nm
The size of nanoparticles ranges between 1 to 100 nm.
Diameter of hydrogen atom is…………….
The diameter of a hydrogen atom is 0.1 nm.
Carbon atoms form………….. bonds with other carbon atoms.
Carbon atoms form covalent bonds with other carbon atoms.
Fullerene or bucky-ball is made-up of………………. carbon atoms.
Fullerene or bucky-ball is made up of 60 carbon atoms.
Thermal conductivity of standard SWNT along its length is…………………… .
Answer the following questions in brief :
What is nanoscience ?
It is a science which gives understanding of materials having dimensions in the range of 1 to 100 nm or less.
Mention the difference between bottom-up approach and top-down approach of synthesizing materials.
Bottom-up approach: In the bottom-up approach of manufacturing devices, positionally controlled changes of atom-by-atom or molecule-by-molecule nanostructures or nanoparticles are designed to achieve the desired properties.
Special techniques are required for the synthesis of nanomaterials. These techniques include grinding (ball-mill) methods, use of thermal plasma, inert-gas condensation, wet-chemical technique or chemical solution deposition, etc.
Top-down approach: It is an ancient technique wherein the manufacturing of devices and synthesising of materials is done by gathering information and understand the properties of big materials from macro to micro level.
Conventional techniques like carving, cutting, bending, moulding, etc. are used for manufacturing of materials, devices or machines.
Give two examples of use of nanostructures from earlier times.
The following are the examples of use of nanostructures from earlier times:
- Damascus steel with carbon nanoparticles was found on the surface of Tipu Sultan’s sword.
- Ancient Egyptians used a nano-lead compound for their eye makeup.
Name two microscopes which are used to develop nanostructures.
The two types of microscopes used to develop nanostructures are:
- Scanning Tunneling Microscope (STM), and
- Atomic Force Microscope (AFM).
What are carbon nanobuds ? Explain in brief.
Carbon nanobuds are a newly discovered allotrope of carbon in which fullerene ‘buds’ are covalently attached to the outer part of carbonnanotubes. This hybrid material has mixed properties of both fullerenes and nanotubes and finds use in some special applications.
Give account of electrical properties of carbon nanotube.
Metallic nanotubes can carry electric current of 109 A per cm2 cross-section of the tube. This value is 1000 times more than that conducted by the metal copper. Multi-walled nanotubes (MWNT) shows superconductivity up to temperature of 12 K.
Name four energy sectors where nanotechnology is useful.
The four energy sectors where nanotechnology is useful are:
- Biofuel energy sector
- Nanowire battery sector
- Concentrated solar power sector
- Wireless energy transfer sector
Name important areas related to nanotechnology.
The important areas related to nanotechnology are:
- Nanotubes and buckyballs
- Synthesis and characterisation
- Metallic nanotubes
- Bio and carbonic nano-sensors
- Nano energy storage devices
Write answer of the following questions :
Explain how surface area to volume ratio is important for nanostructured materials.
- The physical properties of nanostructured materials depend on their size and shape.
- An important parameter which determines the functioning of nanomaterials is the surface area (SA) to volume (V) ratio.
- We know that reaction takes place at the surface of a chemical or a material. The greater the surface area for the same volume of a material, greater is the reactivity.
- Nanostructured materials have large SA to V ratio which improves their reactivity by a large amount.
- Due to large SA/V ratio, friction and sticking effects are very large in nanomaterials.
‘Carbon forms backbone of biology of life on earth’. Justify.
Carbon is found in the form of complex molecules bonded with other elements like oxygen, hydrogen and nitrogen. It is a major constituent of conventional sources of energy. Materials containing carbon, exhibit a wide spectrum of properties due to the following reasons:
- Carbon atom can bond with many different types of atoms including other carbon atoms by forming covalent bonds. Hence, long chains of atoms can be formed. This results in various allotropes like diamond, graphite, graphene, fullerenes, etc. all showing different properties.
- Carbon is the only atom which bonds strongly with other carbon atoms by sharing different number of electrons. This bond is responsible for all necessary biochemical compounds necessary for life.
Thus, carbon is considered as backbone of life on Earth.
Give detailed note on strength of carbon nanotubes.
The tensile strength of a carbon nanotube is very high when compared to bulk materials like steel. This strength is the result of covalent sp2 bonds between carbon-carbon atoms. Example: MWNT has tensile strength of 63 × 109 Pa which is equivalent to having a mass of 6422 kg on a wire of cross-sectional area 1 mm2. However, under excessive tensile strain nanotubes show permanent deformation. Their compressive strength is low. Along the radial direction, nanotubes are much softer which enables them to be bent like a rubber tube.
The hardness of a standard SWNT is about 25 × 109 Pa, while its bulk modulus is higher than diamond. The C60 fullerene in crystalline form has remarkable mechanical properties.
Write a note on thermal properties of carbon nanotubes.
Carbon nanotubes have good thermal conductivity along their length. SWNT has thermal conductivity of about 3500 while the same for copper is 385 at room temperature. Along the axis of the tube, nanotubes are good insulators. Their thermal stability in vacuum is up to 3100 K and only 1000 K in air.
Explain how nanotechnology will be useful in health sector.
- Better, cheaper and faster diagnostics can be attained by higher functional efficiency of nano-devices.
- Accurate and precise diagnosis improves medical treatment.
- A nano drug can be designed which will act only at the infected site thereby reducing the side effects to other metabolic functions. Example: Anticancer drugs can be transported only to the cancerous cells, and upon excitation by a laser beam, these nanodrugs are heated to destroy cancerous cells.
- Carbon nanotubes and their polymer nano-composites are suitable scaffold materials for bone cell proliferation and bone formation.
Answer the following questions in detail :
Justify the statement ‘Nanotechnology plays by different rules.’
The prime goal of nanotechnology is to design nanostructures and nanoparticles for specific applications. It utilises a bottom-up approach wherein special techniques are required to manufacture nanomaterials.
A feature of nanostructures is that their physical properties are dependent on their size and shape. The parameter which determines the functioning of a nanomaterial is the surface area to volume ratio. Greater the SA/V ratio, greater is the reactivity of such materials. Hence, the same material shows different physical properties at the nanoscale.
Also, due to the large SA/V ratio, the friction and sticking effects of such materials is large. Forces among nanomaterials are determined by the laws of quantum mechanics rather than classical mechanics.
Hence, it is said that nanotechnology plays by different rules.
Write a detailed note on bucky-ball.
Spherical fullerenes resemble the ‘football’ used in association with the sport football. Hence, they are known as ‘bucky balls’. They are about 1 nm in diameter.
Existence of fullerene is identified in candle soot and lightning discharge in the atmosphere. In 2010, C60 was found in a cloud of cosmic dust surrounding a star 6500 light years away. It is believed that bucky balls from outer space have provided seeds for life on Earth.
Bucky balls with different C-atoms, C60, C70, C76, C86 are also reported.
Bucky balls are extremely strong. Due to their special bonding among C-atoms, they can easily trap other atoms or molecules. Hence, their purification is a challenge.
Write a detailed note on a nanotube.
Carbon nanotubes are cylindrical fullerenes. They are bucky balls with closing ends which form tube-like structures.
Nanotubes of micrometres to millimetres in length are possible. The carbon nanotube derived from a bucky ball is also called ‘bucky tube’.
Nanotubes can be found with either closed-ends or open-ends. Nanotubes with reducing diameter towards one of the ends can also be designed. Nanotubes with single cylinder called Single Walled Nanotube (SWNT) and multiple concentric nano-cylinders called Multi-Walled Nanotube(MWNT) can be obtained.
Show how nanotechnology is important to us.
- Higher functional efficiency of nano-devices results into better, cheaper and faster diagnosis and drug applications. Accurate and precise diagnosis improves medical treatment.
- Due to tunable electrical and optical properties, specially designed nanomaterials can interchange electricity and light with minimum energy loss.
- Nanomaterials have found large applications in the field of defense due to lighter yet stronger mechanical properties. They are used to construct light and strong battle tanks, spacecrafts, bridges, cranks, etc.
- Researchers have shown that ultra-fast calculators can be made with the help of nanotechnology.