(3) reflection of light due to the presence of free electrons Explanation: Lustre (or luster) is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the latin lux, meaning "light", and generally implies radiance, gloss, or brilliance. Metals in general have high electrical conductivity, high thermal conductivity, and high density. Typically they are malleable and ductile, deforming -under stress without cleaving.

(3) reflection of light due to the presence of free electrons Explanation: Lustre (or luster) is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the latin lux, meaning "light", and generally implies radiance, gloss, or brilliance. Metals in general have high electrical conductivity, high thermal conductivity, and high density. Typically they are malleable and ductile, deforming -under stress without cleaving.
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Cloud is a colloidal dispersion of – (1) Air in a dispersion medium of water (2) Fog in a dispersion medium of water (3) Mist in a dispersion medium of air (4) Water drops in a dispersion medium of air
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The lustre of the metals is because of (1) high density, due to closed packing of atoms (2) high polish (3) reflection of light due to the presence of free electrons (4) absorption of light due to the presence of cavities

Description : The lustre of the metals is because of (1) high density, due to closed packing of atoms (2) high polish (3) reflection of light due to the presence of free electrons (4) absorption of light due to the presence of cavities

Last Answer : reflection of light due to the presence of free electrons

The luster of a metal is due to - (1) high polishing (2) high density (3) chemical inertness (4) presence of free electrons

Description : The luster of a metal is due to - (1) high polishing (2) high density (3) chemical inertness (4) presence of free electrons

Last Answer : (4) presence of free electrons Explanation: Lustre or luster is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the Latin lux, meaning "light", and generally implies radiance, gloss, or brilliance.

(1) they contain free electrons Explanation: Metals typically consist of closepacked atoms, meaning that the atoms are arranged like closely packed spheres. Two packing motifs are common, one being bodycentered cubic wherein each metal atom is surrounded by eight equivalent atoms. The other main motif is face-centered cubic where the metal atoms are surrounded by six neighboring atoms. Several metals adopt both structures, depending on the temperature.

Description : (1) they contain free electrons Explanation: Metals typically consist of closepacked atoms, meaning that the atoms are arranged like closely packed spheres. Two packing motifs are common, one ... surrounded by six neighboring atoms. Several metals adopt both structures, depending on the temperature.

Last Answer : Helium gas is filled in ballons because (1) its atomic number is 2 (2) it is lighter than air (3) it is one of the constitutents of water (4) it is a noble gas

Pick out the wrong statement. (A) Metal/alloys having hexagonal crystal lattice structure are less malleable than those having cubic crystal lattice structure (B) Metal/alloys having body centred cubic (bcc) crystal lattice structure is stronger & less ductile than those having face centred cubic (fcc) crystal lattice structure (C) Tungsten has a body centred cubic (bcc) crystal lattice structure (D) Both ferritic & austenitic stainless steel has a face centred cubic (fcc) crystal structure

Description : Pick out the wrong statement. (A) Metal/alloys having hexagonal crystal lattice structure are less malleable than those having cubic crystal lattice structure (B) Metal/alloys having body centred cubic ... D) Both ferritic & austenitic stainless steel has a face centred cubic (fcc) crystal structure

Last Answer : (C) Tungsten has a body centred cubic (bcc) crystal lattice structure

The silver luster of the metals can be attributed to one of the following. It is attributed to their free w) protons x) ions y) neutrons z) electrons

Description : The silver luster of the metals can be attributed to one of the following. It is attributed to their free w) protons x) ions y) neutrons z) electrons

Last Answer : ANSWER: Z -- ELECTRONS 

Which of the following statements about the physical properties of metal is not correct? (a) All metals are solid except mercury (b) Most metals are hard except sodium and potassium (c) Metals are not malleable (d) Most metals are ductile

Description : Which of the following statements about the physical properties of metal is not correct? (a) All metals are solid except mercury (b) Most metals are hard except sodium and potassium (c) Metals are not malleable (d) Most metals are ductile

Last Answer : Ans:(c)

Why are there a wide range of colours, hardness, crystal forms, lustre and density found in minerals? -SST 10th

Description : Why are there a wide range of colours, hardness, crystal forms, lustre and density found in minerals? -SST 10th

Last Answer : The ranges found in minerals are due to physical and chemical conditions.

Why are there a wide range of colours, hardness, crystal forms, luster and density found in minerals ? -SST 10th

Description : Why are there a wide range of colours, hardness, crystal forms, luster and density found in minerals ? -SST 10th

Last Answer : A wide range of colours, hardness, crystal forms, luster, and density is found in minerals because of the high levels of variations in physical and chemical conditions under which a mineral is formed.

Which company traces its origins back to a store set up by Sotirios Voulgaris in his home village Paramythia in Greece in the 1870s?

Description : Which company traces its origins back to a store set up by Sotirios Voulgaris in his home village Paramythia in Greece in the 1870s?

Last Answer : Bulgari.

Refractory metals are known for which of the following properties: w) lack of chemical reactivity x) low density y) high melting point z) high thermal conductivity

Description : Refractory metals are known for which of the following properties: w) lack of chemical reactivity x) low density y) high melting point z) high thermal conductivity

Last Answer : ANSWER: Y -- HIGH MELTING POINT

The ratio of thermal & electrical conductivity is same for all the metals at the same temperature; and at around room temperature, this ratio is proportional to(where, T = absolute temperature, °K) (A) T (B) 1/T (C) T2 (D) 1/T2

Description : The ratio of thermal & electrical conductivity is same for all the metals at the same temperature; and at around room temperature, this ratio is proportional to(where, T = absolute temperature, °K) (A) T (B) 1/T (C) T2 (D) 1/T2

Last Answer : A) T

On a cold day when the room temperature is 15°C, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15°C, because – (1) metals have higher thermal capacity than plastics (2) plastics have a lower density than metals (3) metals are good conductors of heat (4) plastics have a higher thermal conductivity than metals

Description : On a cold day when the room temperature is 15°C, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15°C, because - (1) metals ... metals (3) metals are good conductors of heat (4) plastics have a higher thermal conductivity than metals

Last Answer : (3) metals are good conductors of heat Explanation: On a chilly day, the room temperature is lower than our body temperature. Since metals have a higher coefficient of thermal conductivity than plastic, they ... from our fingers will flow to the metal cap much more quickly than to the plastic body.

On a cold day when the room temperature is 15°C, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15°C, because : (1) metals have higher thermal capacity than plastics (2) plastics have a lower density than metals (3) metals are good conductors of heat (4) plastics have a higher thermal conductivity than metals

Description : On a cold day when the room temperature is 15°C, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15°C, because : (1) metals ... metals (3) metals are good conductors of heat (4) plastics have a higher thermal conductivity than metals

Last Answer : metals are good conductors of heat

The crystal of diamond shines due to (a) High density (b) Total internal reflection (c) Crystal lattice (d) None of these

Description : The crystal of diamond shines due to (a) High density (b) Total internal reflection (c) Crystal lattice (d) None of these

Last Answer : Ans:(b)

In a three-phase electrical system, three ground detecting lamps are provided. If all three lamps REMAIN at half-brilliance when the ground detecting test switch is operated, ______________. A. there is a slight ground on all three phases B. the switch must be replaced C. there are no grounds present D. the light bulbs are of improper voltage

Description : In a three-phase electrical system, three ground detecting lamps are provided. If all three lamps REMAIN at half-brilliance when the ground detecting test switch is operated, ______________. A. there is a ... must be replaced C. there are no grounds present D. the light bulbs are of improper voltage

Last Answer : Answer: C

Wrought iron is (A) High carbon iron (B) Highly resistance to acid corrosion (C) Malleable & ductile; and hence is used for chain links, hooks & couplings (D) An alloy of iron, chromium & carbon

Description : Wrought iron is (A) High carbon iron (B) Highly resistance to acid corrosion (C) Malleable & ductile; and hence is used for chain links, hooks & couplings (D) An alloy of iron, chromium & carbon

Last Answer : (C) Malleable & ductile; and hence is used for chain links, hooks & couplings

The luster of diamond is due to-----? A. Reflection B. Total internal reflection (Answer) C. Refraction D. None of these

Description : The luster of diamond is due to-----? A. Reflection B. Total internal reflection (Answer) C. Refraction D. None of these

Last Answer : B. Total internal reflection (Answer)

What is the high electrical conductivity of metals is primarily due to?

Description : What is the high electrical conductivity of metals is primarily due to?

Last Answer : In metals electrons are in a free movement.

Dittus-Boelter equation cannot be used for molten metals mainly due to its very low (A) Prandtl number (B) Grashoff number (C) Thermal conductivity (D) Viscosity

Description : Dittus-Boelter equation cannot be used for molten metals mainly due to its very low (A) Prandtl number (B) Grashoff number (C) Thermal conductivity (D) Viscosity

Last Answer : (A) Prandtl number

What type of solid is ductile and malleable?

Description : What type of solid is ductile and malleable?

Last Answer : Several metals are ductile and malleable.

If a metal can be drawn into wires relatively easily it is called: (1) malleable (2) ductile (3) extractive (4) tactile

Description : If a metal can be drawn into wires relatively easily it is called: (1) malleable (2) ductile (3) extractive (4) tactile

Last Answer : (2) ductile Explanation: Ductility is a physical property of a material associated with the ability to be hammered thin or stretched into wire without breaking.

Polystyrene is a __________ plastic at room temperature. (A) Ductile (B) Brittle (C) Malleable (D) None of these

Description : Polystyrene is a __________ plastic at room temperature. (A) Ductile (B) Brittle (C) Malleable (D) None of these

Last Answer : (B) Brittle

Zinc is highly __________ at room temperature. (A) Ductile (B) Resistant to atmospheric corrosion (C) Malleable (D) Brittle

Description : Zinc is highly __________ at room temperature. (A) Ductile (B) Resistant to atmospheric corrosion (C) Malleable (D) Brittle

Last Answer : (B) Resistant to atmospheric corrosion

A material capable of undergoing large permanent deformation, when subjected to compression is termed as (A) Malleable (B) Ductile (C) Brittle (D) None of these

Description : A material capable of undergoing large permanent deformation, when subjected to compression is termed as (A) Malleable (B) Ductile (C) Brittle (D) None of these

Last Answer : (A) Malleable

Cast iron is a __________ material. (A) Brittle (B) Ductile (C) Tough (D) Malleable

Description : Cast iron is a __________ material. (A) Brittle (B) Ductile (C) Tough (D) Malleable

Last Answer : (A) Brittle

Steel produced from phosphatic iron is __________ in nature. (A) Malleable (B) Ductile (C) Brittle (D) Tough

Description : Steel produced from phosphatic iron is __________ in nature. (A) Malleable (B) Ductile (C) Brittle (D) Tough

Last Answer : (C) Brittle

__________ iron is produced by the annealing of white cast iron. (A) Malleable (B) Nodular (C) Ductile (D) Grey

Description : __________ iron is produced by the annealing of white cast iron. (A) Malleable (B) Nodular (C) Ductile (D) Grey

Last Answer : (A) Malleable

Increasing sulphur content in pig iron tends to make it (A) Soft (B) Hard (C) Tough (D) Ductile & malleable

Description : Increasing sulphur content in pig iron tends to make it (A) Soft (B) Hard (C) Tough (D) Ductile & malleable

Last Answer : Option B

The most malleable, ductile low resistivity material is (A) Copper. (B) Aluminium. (C) Silver. (D) Iron.

Description : The most malleable, ductile low resistivity material is (A) Copper. (B) Aluminium. (C) Silver. (D) Iron.

Last Answer : (C) Silver.

If a metal can be drawn into wires relatively easily it is called: w) malleable x) ductile y) extractive z) tactile

Description : If a metal can be drawn into wires relatively easily it is called: w) malleable x) ductile y) extractive z) tactile

Last Answer : ANSWER: X -- DUCTILE

Among liquids, water has a comparatively high value of thermal conductivity, due to its (A) Low density (B) High viscosity (C) Partial ionisation (D) Dense structure

Description : Among liquids, water has a comparatively high value of thermal conductivity, due to its (A) Low density (B) High viscosity (C) Partial ionisation (D) Dense structure

Last Answer : (C) Partial ionisation

(4) water and petrol are immiscible with each other and petrol which forms the upper layer continues to burn Explanation: Water is not effective in extinguishing a fire caused by petrol because water and petrol are immiscible with each other and petrol which forms the upper layer continues to burn. The specific gravity (or relative density) of gasoline ranges from 0.71-0.77 kg/l (719.7 kg/m3) while the specific gravity of water is 1000 kg/m3 and that is why gasoline or petrol floats on the upper surface of the water. Water cannot generally be used to extinguish a gasoline fire, unless used in a fine mist.

Description : (4) water and petrol are immiscible with each other and petrol which forms the upper layer continues to burn Explanation: Water is not effective in extinguishing a fire caused by petrol because water and ... . Water cannot generally be used to extinguish a gasoline fire, unless used in a fine mist.

Last Answer : "All the four quantum numbers of two electrons in an atom are not the same." It is the law of (1) Hund’s (2) Exclusion Principle of Pauli (3) Uncertainty Principle of Giesenberg (4) Avogadro’s law

Power consumption during turbulent flow in agitation tank is proportional to the __________ of the liquid. (A) Viscosity (B) Thermal conductivity(C) Surface tension(D) Density

Description : Power consumption during turbulent flow in agitation tank is proportional to the __________ of the liquid. (A) Viscosity (B) Thermal conductivity (C) Surface tension (D) Density

Last Answer : (D) Density

Which of the following properties of a solid is not dependent on crystal imperfection? (A) Ductility (B) Semi-conductivity (C) Melting point (D) Yield stress

Description : Which of the following properties of a solid is not dependent on crystal imperfection? (A) Ductility (B) Semi-conductivity (C) Melting point (D) Yield stress

Last Answer : (C) Melting point

Assertion:- Ionic compounds exhibits electrical conductivity in solution state. Reason :- In solution state electrons of ionic compounds are free.

Description : Assertion:- Ionic compounds exhibits electrical conductivity in solution state. Reason :- In solution state electrons of ionic compounds are free.

Last Answer : Assertion:- Ionic compounds exhibits electrical conductivity in solution state. Reason :- In solution state ... . If both Assertion & Reason are false

(2) stabilise the colloid and prevent crystallisation Explanation: Gelatine, being a colloid, has the property of preventing crystallization. In ice lollies and icecream this is demonstrated by the formation of a very fine crystal structure on freezing. This goes much further in that gelatine stabilized icecream does not become grainy or sandy due to the slow crystallisation of lactose with time.

Description : (2) stabilise the colloid and prevent crystallisation Explanation: Gelatine, being a colloid, has the property of preventing crystallization. In ice lollies and icecream this is demonstrated by the formation ... does not become grainy or sandy due to the slow crystallisation of lactose with time.

Last Answer : Glycol is added to aviation gasoline because it - (1) reduces evaporation of petrol (2) increases efficiency of petrol (3) prevents freezing of petrol (4) reduces consumption of petrol

(A) Ether behaves as bases in the presence of mineral acids. (R ) Due to the presence of lone pair of electrons on oxygen.

Description : (A) Ether behaves as bases in the presence of mineral acids. (R ) Due to the presence of lone pair of electrons on oxygen.

Last Answer : (A) Ether behaves as bases in the presence of mineral acids. (R ) Due to the presence of lone pair of ... R is false D. A is false but R is true

(A) Ether behaves as bases in the presence of mineral acids. (R ) Due to the presence of lone pair of electrons on oxygen.

Description : (A) Ether behaves as bases in the presence of mineral acids. (R ) Due to the presence of lone pair of electrons on oxygen.

Last Answer : (A) Ether behaves as bases in the presence of mineral acids. (R ) Due to the presence of lone pair of ... R is false D. A is false but R is true

Which physical properties of a given mineral displays the greatest variation A) color B) hardness C) luster D) streak

Description : Which physical properties of a given mineral displays the greatest variation A) color B) hardness C) luster D) streak

Last Answer : color

(2) experience collision less frequently Explanation: When an electric field is applied, both the valence electrons and the free electrons move in the same direction. The hole direction is opposite to that of valence electron but the mobility is the same. Even for the same electric field, valence electrons cannot move as freely as the free electrons because its movement is restricted due to collisions. Therefore, the velocity of valence electrons is less compared to free electrons. In other words, the velocity of holes is less compared to free electrons. This means mobility is also less for a hole compared to free electron.

Description : (2) experience collision less frequently Explanation: When an electric field is applied, both the valence electrons and the free electrons move in the same direction. The hole direction is opposite to that ... to free electrons. This means mobility is also less for a hole compared to free electron.

Last Answer : Carbon dioxide is called a greenhouse gas because - (1) its concentration remains always higher than other gases (2) it is used in photosynthesis (3) it absorbs infrared radiation (4) it emits visible radiation

What is the maximum value of deforming force upto which a material shows elastic property and above which the material loses it? (1) Elasticity (2) Strain (3) Elastic Limit (4) Stress

Description : What is the maximum value of deforming force upto which a material shows elastic property and above which the material loses it? (1) Elasticity (2) Strain (3) Elastic Limit (4) Stress

Last Answer : (3) Elastic Limit Explanation: The Maximum Extent to which a solid may be stretched without permanent alteration of size or shape.

What is the maximum value of deforming force up to which a material shows elastic property and above which the material loses it? (1) Elasticity (2) Strain (3) Elastic Limit (4) Stress

Description : What is the maximum value of deforming force up to which a material shows elastic property and above which the material loses it? (1) Elasticity (2) Strain (3) Elastic Limit (4) Stress

Last Answer : (4) Elastic Limit Explanation: The Maximum Extent to which a solid may be stretched without permanent alteration of size or shape.

Coke oven regenerators are made of __________ bricks. (A) Fire clay (B) Silica (C) Low thermal conductivity (D) High electrical conductivity

Description : Coke oven regenerators are made of __________ bricks. (A) Fire clay (B) Silica (C) Low thermal conductivity (D) High electrical conductivity

Last Answer : (A) Fire clay

Dielectric (A) Is an electrical insulating material (B) Of low resistivity is preferred (C) Should have high thermal conductivity (D) Need not defy the corrosive action of chemicals

Description : Dielectric (A) Is an electrical insulating material (B) Of low resistivity is preferred (C) Should have high thermal conductivity (D) Need not defy the corrosive action of chemicals

Last Answer : (A) Is an electrical insulating material

Pick out the wrong statement. (A) Copper is the metal having the highest electronic conductivity (B) Hardenability & Weldability of metals are inversely related (C) Covalent bonding formed by sharing of electrons is present in all semiconductor materials (D) Glass transition temperature applies to 'polymers' but not to 'glasses'

Description : Pick out the wrong statement. (A) Copper is the metal having the highest electronic conductivity (B) Hardenability & Weldability of metals are inversely related (C) Covalent bonding formed by ... all semiconductor materials (D) Glass transition temperature applies to 'polymers' but not to 'glasses'

Last Answer : Option A

It is the intensity of a radiating source.  a. Specific Brightness  b. Radiance  c. Surface Brightness  d. All of these

Description : It is the intensity of a radiating source.  a. Specific Brightness  b. Radiance  c. Surface Brightness  d. All of these

Last Answer : All of these

Which °fine metals has the maximum thermal conductivity? (1) Iron (2) Aluminium (3) Silver (4) Copper

Description : Which °fine metals has the maximum thermal conductivity? (1) Iron (2) Aluminium (3) Silver (4) Copper

Last Answer : (3) Silver Explanation: Silver has the best thermal conductivity of 429 W/mK at RT (295K). It is followed by copper, gold and aluminium. Metals generally have very good electrical conductivity, that leads to high thermal conductivity.

Which of the following liquid metals has the highest thermal conductivity? (A) Molten sodium (B) Molten lead (C) Mercury (D) Molten potassium

Description : Which of the following liquid metals has the highest thermal conductivity? (A) Molten sodium (B) Molten lead (C) Mercury (D) Molten potassium

Last Answer : (A) Molten sodium

A bimetallic strip commonly found in home furnace thermostats works because of the difference in this property of the two metals. Is it: w) thermal shock x) thermal conductivity y) thermal expansion z) thermal diffusivity

Description : A bimetallic strip commonly found in home furnace thermostats works because of the difference in this property of the two metals. Is it: w) thermal shock x) thermal conductivity y) thermal expansion z) thermal diffusivity

Last Answer : ANSWER: Y -- THERMAL EXPANSION

Which of the metals has the maximum thermal conductivity? (1) Iron (2) Aluminium (3) Silver (4) Copper

Description : Which of the metals has the maximum thermal conductivity? (1) Iron (2) Aluminium (3) Silver (4) Copper

Last Answer : Silver