Q35. Which of the following substances has the highest resistivity?
[RRB Group D 2025-cycle Official Paper (21 August 2026, Shift 1)]
(A) Manganin
(B) Silver
(C) Tungsten
(D) Iron
Answer: (A) Manganin
Explanation: Manganin is a copper–manganese–nickel alloy with much greater electrical resistivity than the three pure metals listed. Its resistance changes very little with temperature, making it useful in precision resistance standards and meter shunts. Silver, by contrast, is an excellent electrical conductor.
Q34. Why are alloys preferred for heating elements in appliances like toasters?
[RRB Group D 2025-cycle Official Paper (3 August 2026, Shift 1)]
(A) Because they have high resistivity and do not easily oxidize at high temperatures
(B) Because they are electrical insulators
(C) Because they are electrical conductors with low resistivity
(D) They have a low melting point
Answer: (A) Because they have high resistivity and do not easily oxidize at high temperatures
Explanation: Heating-element alloys such as nichrome combine high electrical resistivity with heat resistance and resistance to oxidation. They generate substantial heat when current flows yet remain stable at operating temperatures. A good heating wire must conduct electricity, so being an insulator is not desirable.
Q33. An alloy P contains 20% copper and 80% zinc by weight. Alloy Q contains 60% copper and 40% zinc. In what ratio should P and Q be mixed to obtain an alloy containing equal amounts of copper and zinc?
[UPSC Civil Services Preliminary Examination 2026, CSAT Paper]
(A) 1 : 3
(B) 3 : 1
(C) 2 : 3
(D) 3 : 2
Answer: (A) 1 : 3
Explanation: The final mixture must contain 50% copper. Alloy P has 20% copper and alloy Q has 60%. By alligation, P : Q = (60 − 50) : (50 − 20) = 10 : 30 = 1 : 3. Zinc then also constitutes 50%.
Q32. Brass is an example of:
[RRB Group D Official Paper (17 December 2025, Shift 3)]
(A) An element
(B) A compound
(C) A homogeneous mixture
(D) A heterogeneous mixture
Answer: (C) A homogeneous mixture
Explanation: Brass contains copper and zinc mixed at the metallic level. In a uniform brass sample, the components form a homogeneous solid mixture, rather than a chemical compound with one fixed formula. Varying the proportions of copper and zinc produces brass grades with different properties.
Q31. Which of the following has a variable composition?
[RRB Group D Official Paper (11 December 2025, Shift 3)]
(A) Hydrogen chloride
(B) Water
(C) Methane
(D) Brass
Answer: (D) Brass
Explanation: Brass is a copper–zinc alloy whose proportions may change according to the intended use. Hydrogen chloride, water and methane are compounds with definite chemical formulas. Alloys generally do not have a single fixed chemical formula, because their constituent proportions can vary.
Q30. Alloy X has copper and zinc in the ratio 5 : 4, and alloy Y has them in the ratio 5 : 13. If equal quantities of X and Y are mixed, what is the ratio of copper to zinc in the resulting alloy?
[UPSC CDS-II 2025, Elementary Mathematics (14 September 2025)]
(A) 5 : 8
(B) 5 : 7
(C) 6 : 7
(D) 7 : 8
Answer: (B) 5 : 7
Explanation: Take 18 units of each alloy. X then has 10 units copper and 8 zinc; Y has 5 copper and 13 zinc. The combined alloy contains 15 copper and 21 zinc, giving the reduced ratio 5 : 7.
Q29. Which copper-based alloy is preferred for making standard resistors because of its high resistivity and low temperature coefficient?
[RRB NTPC Undergraduate CBT-I (4 September 2025, Shift 3)]
(A) Alnico
(B) Manganin
(C) Tungsten
(D) Brass
Answer: (B) Manganin
Explanation: Manganin consists mainly of copper with manganese and nickel. Its comparatively high resistivity is useful in resistor construction, while its very small temperature coefficient helps resistance remain stable during measurement. These properties make manganin suitable for standard resistors and instrument shunts.
Q28. Why is an alloy considered a mixture even though it cannot be separated by ordinary physical methods?
[RRB NTPC Undergraduate CBT-I (13 August 2025, Shift 3)]
(A) It is formed only by non-metals
(B) It shows the properties of its constituents and can have variable composition
(C) It contains only one type of element in vapour form
(D) All alloys are magnetic because their composition is fixed
Answer: (B) It shows the properties of its constituents and can have variable composition
Explanation: An alloy combines elements without necessarily producing a single compound of fixed stoichiometry. Its component proportions can vary, and its physical characteristics depend on those constituents. Separating atoms within a solid alloy is difficult, but difficulty of separation does not make it a pure compound.
Q27. Assertion (A): An alloy of lead and tin is generally used for fuse wire.
Reason (R): Lead–tin alloy has a higher melting point than copper and aluminium.
Choose the correct statement.
[UPPSC PCS Preliminary Examination 2025, General Studies Paper I]
(A) Both A and R are true, and R correctly explains A
(B) A is true, but R is false
(C) A is false, but R is true
(D) Both A and R are true, but R does not explain A
Answer: (B) A is true, but R is false
Explanation: Traditional fuse alloys may use lead and tin because they melt at temperatures much lower than copper or aluminium. Excess current raises the wire temperature until it breaks the circuit. Therefore the assertion is correct but the claimed higher melting point is false.
Q26. Bronze is an alloy of:
[MPSC Group B Combined Preliminary Examination 2024 (held 2 February 2025)]
(A) Copper and tin
(B) Copper and zinc
(C) Copper and lead
(D) Copper and nickel
Answer: (A) Copper and tin
Explanation: Bronze traditionally combines copper with tin. Adding tin increases copper’s hardness and improves several wear and corrosion properties. Bronze has long been used for sculptures, coins, tools, bearings and other cast articles. Brass, in comparison, is primarily copper and zinc.
Q25. Which type of alloy is formed when a metalloid or non-metal is dissolved in a metal?
[DSSSB Assistant Engineer (Civil) Official Paper (22 June 2024, Shift 2)]
(A) Composite alloy
(B) Interstitial alloy
(C) Amorphous alloy
(D) Substitutional alloy
Answer: (B) Interstitial alloy
Explanation: In an interstitial alloy, comparatively small atoms occupy spaces between the larger metal atoms in the crystal lattice. Carbon in iron is a familiar example. Such solute atoms impede dislocation movement and can increase hardness and strength, depending on composition and treatment.
Q24. Which property is NOT correct for nichrome wire used in electrical heating appliances?
[NCL Assistant Foreman Trainee (Electrical) (4 March 2024, Shift 2)]
(A) It can withstand thermal stress
(B) It has a high temperature coefficient
(C) It has high specific resistance
(D) It has good mechanical strength
Answer: (B) It has a high temperature coefficient
Explanation: Nichrome has high resistivity, withstands elevated operating temperatures and resists oxidation. Its resistance is comparatively stable with changes in temperature, so describing it as having a high temperature coefficient is the incorrect statement. These qualities explain its frequent use in heating appliances.
Q23. What type of mixture is steel?
[Bihar D.El.Ed Official Paper (24 April 2024, Shift 2)]
(A) Alloy
(B) Suspension
(C) Solution
(D) Colloid
Answer: (A) Alloy
Explanation: Steel is an alloy based principally on iron and carbon, with other elements sometimes added to modify its properties. Alloying can improve strength, hardness and corrosion performance. Steel is neither a colloid nor a suspension; in basic general-science classification, it belongs to alloys.
Q22. Which one of the following alloys contains a non-metal as one of its constituents?
[UPSC NDA-II General Ability Test (3 September 2023)]
(A) Brass
(B) Bronze
(C) Amalgam
(D) Steel
Answer: (D) Steel
Explanation: Steel contains iron and carbon, and carbon is a non-metal. Brass combines copper and zinc, while traditional bronze combines copper and tin. Amalgam denotes an alloy involving mercury and another metal. Thus steel is the choice that clearly includes a non-metal constituent.
Q21. Which of the following has the highest resistivity?
[SSC CGL Tier I (17 July 2023, Shift 1)]
(A) Silver
(B) Nichrome
(C) Chromium
(D) Iron
Answer: (B) Nichrome
Explanation: Nichrome is a nickel–chromium-based alloy specially valued for its high resistivity. It converts electrical energy into heat efficiently and tolerates high operating temperatures. Silver is one of the best conductors, while iron and chromium have lower resistivity than typical nichrome heating alloys.
Q20. Which s-block element is used in alloys with copper or nickel for gyroscopes, springs, electrical contacts and non-sparking equipment?
[SSC CHSL Tier I (2 August 2023, Shift 4)]
(A) Beryllium
(B) Rubidium
(C) Francium
(D) Caesium
Answer: (A) Beryllium
Explanation: Beryllium is a lightweight group 2 metal. Small additions to copper produce beryllium-copper alloys with high strength, elasticity and wear resistance. Such alloys are suitable for springs, electrical contacts and non-sparking tools. Rubidium, francium and caesium are much more reactive alkali metals.
Q19. Which of the following metals is always a component of an amalgam?
[SSC MTS 2022-cycle Official Paper (15 June 2023, Shift 1)]
(A) Strontium
(B) Mercury
(C) Zinc
(D) Aluminium
Answer: (B) Mercury
Explanation: An amalgam is an alloy that contains mercury. The other metallic component may vary: examples involve silver, tin, copper and certain other metals. Mercury’s ability to combine with many metals underlies historical applications in dentistry and metallurgy, although mercury exposure presents health risks.
Q18. Duralumin is an alloy made up of aluminium and ________.
[SSC GD Constable 2022-cycle Official Paper (17 January 2023, Shift 4)]
(A) Nickel
(B) Tin
(C) Copper
(D) Zinc
Answer: (C) Copper
Explanation: Duralumin is an aluminium alloy in which copper is an important strengthening constituent. Commercial varieties also include magnesium and manganese. It offers a useful strength-to-weight ratio and was historically important in aircraft structures. It is different from brass, a copper–zinc alloy.
Q17. Which material is preferably used in making heating elements of electrical heating devices?
[RRB Group D (23 August 2022, Shift 1)]
(A) Tin–lead alloy
(B) Nichrome
(C) Tungsten
(D) Constantan
Answer: (B) Nichrome
Explanation: Nichrome combines high electrical resistivity, relatively high operating-temperature capability and good oxidation resistance. These properties allow an electrically powered heating element to produce heat without rapidly deteriorating. Tungsten is more associated with lamp filaments, while constantan is widely used in resistance applications.
Q16. Continuous chips can be produced during machining of which of the following materials?
[MPPSC Assistant Engineer (Mechanical) (3 July 2022)]
(A) Brass
(B) Bronze
(C) Cast iron
(D) Copper
Answer: (D) Copper
Explanation: Copper is highly ductile and can deform plastically into continuous chips during machining under suitable cutting conditions. Cast iron is relatively brittle and usually forms discontinuous chips. Brass and bronze are copper-based alloys, but their machinability and chip formation depend on their particular compositions.
Q15. Solder used for joining metal parts together is an alloy of:
[WBCS Preliminary Examination (22 August 2021)]
(A) Iron and copper
(B) Iron and zinc
(C) Tin and copper
(D) Tin and lead
Answer: (D) Tin and lead
Explanation: Traditional soft solder is made using tin and lead. It melts at a lower temperature than the pieces being joined, enabling a metallurgical connection without melting the base metals. Modern electronics increasingly uses lead-free solders for environmental and health reasons.
Q14. Identify the alloy among the following of which lead is a component.
[SSC MTS 2020-cycle Official Paper (26 October 2021, Shift 1)]
(A) Alnico
(B) Solder
(C) Nickel
(D) Constantan
Answer: (B) Solder
Explanation: Conventional soft solder is an alloy of tin and lead. Alnico is an alloy associated with aluminium, nickel and cobalt; constantan is mainly copper and nickel; and nickel is itself an element. Tin–lead solder has a comparatively low melting temperature.
Q13. An alloy is made by mixing metal A costing Rs. 1,000/kg and metal B costing Rs. 700/kg in the ratio 2 : 3. What is the cost of 15 kg of the alloy?
[CGPSC Civil Services 2020, CSAT Paper II]
(A) Rs. 9,800
(B) Rs. 8,200
(C) Rs. 12,300
(D) Rs. 12,800
Answer: (C) Rs. 12,300
Explanation: A 2 : 3 ratio in 15 kilograms gives 6 kilograms of metal A and 9 kilograms of metal B. The cost is (6 × 1,000) + (9 × 700), or Rs. 12,300. This is a weighted average based on constituent quantities.
Q12. Which metal is NOT a constituent of the alloy called German silver?
[SSC Junior Engineer (Civil) (25 September 2019, Morning)]
(A) Copper
(B) Zinc
(C) Silver
(D) Nickel
Answer: (C) Silver
Explanation: German silver, also called nickel silver, normally combines copper, zinc and nickel. Despite its name and silver-white appearance, it contains no elemental silver. The alloy can be used for cutlery, decorative fittings, instruments and other applications requiring an attractive finish.
Q11. Gunmetal is an alloy of:
[SSC MTS (2 August 2019, Shift 2)]
(A) Copper, zinc and lead
(B) Copper, lead and silver
(C) Copper, tin and zinc
(D) Copper, iron and nickel
Answer: (C) Copper, tin and zinc
Explanation: Gunmetal is a copper-based casting alloy mainly containing copper, tin and zinc. Some formulations also add lead. Its combination of strength, castability and resistance to corrosion makes it useful for valves, gears, bearings and pump or steam fittings.
Q10. Brass is a mixture of:
[WBCS Preliminary Examination 2019]
(A) Copper and zinc
(B) Copper and tin
(C) Copper, nickel and zinc
(D) Copper, aluminium and magnesium
Answer: (A) Copper and zinc
Explanation: Brass is principally copper mixed with zinc. Changing the zinc percentage changes its colour, strength and workability. Copper–tin alloy is commonly called bronze; a copper–zinc–nickel alloy is often called German silver. Brass is used for hardware, fittings and musical instruments.
Q9. Gold and copper are present in two alloys in the ratios 7 : 2 and 7 : 11. Equal quantities of both are mixed. What is the gold-to-copper ratio in the third alloy?
[RPSC RAS Preliminary Examination 2018]
(A) 7 : 5
(B) 7 : 12
(C) 14 : 13
(D) 2 : 11
Answer: (A) 7 : 5
Explanation: Choose 18 units of each alloy. The first contains 14 gold and 4 copper; the second contains 7 gold and 11 copper. The combined mixture has 21 units gold and 15 copper, which simplifies to 7 : 5.
Q8. Constantan is alloyed from which metals?
[RRC/RRB Group D (17 September 2018, Shift 2)]
(A) Nickel, titanium, iron and chromium
(B) Copper, nickel and manganese
(C) Nickel, chromium, manganese and iron
(D) Copper and nickel
Answer: (D) Copper and nickel
Explanation: Constantan is primarily an alloy of copper and nickel, often close to 55% copper and 45% nickel. Its electrical resistance varies comparatively little with temperature, making it useful in resistance wires, thermocouples and certain measurement instruments.
Q7. Which one of the following mixtures is homogeneous?
[SSC CHSL (21 March 2018, Shift 2)]
(A) Water and oil
(B) Starch and sugar crystals
(C) Graphite and charcoal
(D) Alloys
Answer: (D) Alloys
Explanation: Many common alloys are homogeneous mixtures because their components are distributed uniformly at the material scale. Brass and bronze are familiar examples. Oil and water separate into different phases, while the other options do not represent the same kind of uniform metallic mixture.
Q6. What are the main components of the alloy bronze?
[SSC CGL Tier I (16 August 2017, Shift 1)]
(A) Copper and zinc
(B) Copper and tin
(C) Zinc and nickel
(D) Aluminium and nickel
Answer: (B) Copper and tin
Explanation: Traditional bronze is an alloy of copper and tin. Tin increases hardness and makes copper more useful for castings, tools, statues and bearings. Copper with zinc forms brass instead. Different bronze grades may also include small quantities of other elements.
Q5. German silver is used to make ornaments and decorative articles. Why is this name given?
[UPSC CDS General Knowledge (14 February 2016)]
(A) It is a copper alloy containing silver
(B) Germans were the first to use silver
(C) Its appearance resembles silver
(D) It is an alloy of silver
Answer: (C) Its appearance resembles silver
Explanation: German silver, or nickel silver, is named for its silvery appearance rather than actual silver content. It typically contains copper, nickel and zinc. The resulting metal is fairly hard and corrosion-resistant and is useful for decorative items, utensils and instrument components.
Q4. Bronze is an alloy of:
[UPPSC Civil Services Preliminary Examination (10 May 2015)]
(A) Copper and tin
(B) Copper and silver
(C) Copper and zinc
(D) Copper and lead
Answer: (A) Copper and tin
Explanation: Bronze mainly contains copper and tin. The addition of tin gives copper greater hardness and makes the material suitable for durable cast objects. Bronze has been used since antiquity for implements, coins and sculptures. Copper combined with zinc forms brass.
Q3. German silver is an alloy of:
[IB ACIO Grade II Paper I (23 September 2012)]
(A) Copper, zinc and nickel
(B) Silver, copper and carbon
(C) Silver, zinc and aluminium
(D) Aluminium, zinc and cobalt
Answer: (A) Copper, zinc and nickel
Explanation: German silver is a copper alloy containing nickel and zinc. Nickel provides the characteristic silver-like colour, while the combined metals produce useful strength and corrosion resistance. Despite the name, ordinary German silver does not contain silver and is also called nickel silver.
Q2. An Invar tape is made of an alloy of:
[JKPSC Assistant Engineer (Civil) Official Paper 2009]
(A) Brass and steel
(B) Nickel and steel
(C) Copper and steel
(D) Copper and brass
Answer: (B) Nickel and steel
Explanation: Invar is an iron–nickel alloy containing about 36% nickel, known for exceptionally low thermal expansion near room temperature. Surveying tapes made from Invar change length very little with temperature, supporting accurate distance measurement. The paper expresses its composition as nickel and steel.
Q1. What are the main constituents of Babbitt metal used in industry?
[MPSC Assistant Motor Vehicle Inspector Official Paper 3 (2002)]
(A) Copper, tin and antimony
(B) Copper, tin and phosphorus
(C) Copper, tin and nickel
(D) Copper, zinc and nickel
Answer: (A) Copper, tin and antimony
Explanation: Tin-based Babbitt bearing metal commonly contains tin, antimony and copper, for example approximately 88% tin, 8% antimony and 4% copper. It provides a comparatively soft, low-friction bearing surface. Other Babbitt formulations are lead-based and use different constituent proportions.