Description : When hot-water is sprinkled on a hotter glass tumbler, it breaks because – (1) glass suddenly expands (2) glass suddenly contracts (3) water evaporates (4) glass reacts chemically with water
Last Answer : (2) glass suddenly contracts Explanation: If the poured liquid is relatively hotter or colder in comparison to the tumbler, it will break. When hot water is poured into a tumbler there is an uneven increase in the thermal expansion of the walls of the vessel.
Description : When hot liquid is poured into a thick glass tumbler, it cracks because glass – (1) is a bad conductor of heat so only inner surface expands (2) has high temperature coefficient of expansion (3) has a very low specific heat (4) has low temperature coefficient of expansion
Last Answer : (1) is a bad conductor of heat so only inner surface expands Explanation: When hot liquid is poured into a thick glass tumbler, it cracks because glass is a bad conductor of heat so only inner surface expands.
Description : When hot liquid is poured into a thick glass tumbler, it cracks because glass : (1) is a bad conductor of heat so only inner surface expands (2) has high temperature coefficient of expansion (3) has a very low specific heat (4) has low temperature coefficient of expansion
Last Answer : is a bad conductor of heat so only inner surface expands
Description : Water pipes in hilly areas often burst on a cold frosty night, because – (1) The material of which pipes are made contracts due to cold and so breaks (2) Water in the pipes freezes and on freezing water expands, so pipes break (3) Frost makes the pipes rusty, so they break (4) None of these
Last Answer : (2) Water in the pipes freezes and on freezing water expands, so pipes break Explanation: The temperature may fall below 0° C during cold frosty nights which converts the water inside the pipes into ice, ... in an increase in volume. This exerts great force on the pipes and as a result, they burst.
Description : Water pipes in hilly areas often burst on a cold frosty night, because (1) the material of which pipes are made contracts due to cold and so breaks (2) water in the pipes freezes and on freezing water expands, so pipes break (3) frost makes the pipes rusty, so they break (4) None of these
Last Answer : water in the pipes freezes and on freezing water expands, so pipes break
Description : When water is filled in a bottle and is allowed to freeze, the bottle breaks because _____? A. Water expands on freezing B. Bottle contracts at freezing point C. Temperature outside the bottle is less than that inside the bottle D. None of them
Last Answer : ANSWER: A
Description : When water is filled in a bottle and is allowed to freeze, the bottle breaks because A. Water expands on freezing (Answer) B. Bottle contracts at freezing point C. temperature outside the bottle is less than that inside the bottle. D. None of the above
Last Answer : A. Water expands on freezing (Answer)
Description : A pyrex tumbler does not crack when hot water is poured into it because pyrex (a) is a strong material (b) does not expand much on heating (c) is a good conductor of heat (d) expands equally from inside and outside
Last Answer : Ans:(b)
Description : When a ring of metal is heated what happens to its hole? (1) expands (2) contracts (3) it expands or contracts according to its diameter (4) it expands or contracts according to its coefficient of expansion
Last Answer : (1) expands Explanation: The hole size will increase because in expansion the size between two molecules, do not increase so when the molecules on the outer edge move outward. Due to expansion, the ... expansion is the tendency of matter to change in volume in response to a change in temperature.
Description : When a ring of metal is heated what happens to its hole ? (1) expands (2) contracts (3) it expands or contracts according to its diameter (4) it expands or contracts according to its coefficient of expansion
Last Answer : expands
Description : Why does a thick glass tumbler crack when boiling hot water is poured into it?
Last Answer : Matter expands when it is heated. When you pour boiling waterinto a glass the bottom becomes heated and expands while the restof the glass is at a different temperature. As the ... expand evenly, preventing that stress from happening. Slow andeven temperature changes will prevent the breaking.
Description : After long periods of use, a grey spot develops on the inside of a bulb. This is because – (1) the tungsten filament evaporates and collects there (2) the heat of the bulb scorches the glass at the top (3) dust inside the bulb condenses on the top (4) glass undergoes a change due to the heat
Last Answer : (3) dust inside the bulb condenses on the top Explanation: At high operating temperatures, tungsten evaporates from the filament and gradually forms a gray film on the inside of the bulb. The inert ... spot develops in the filament. When this happens, the filament will break and the bulb fails.
Description : After long periods of use, a grey spot develops on the inside of a bulb. This is because (1) the tungsten filament evaporates and collects there (2) the heat of the bulb scorches the glass at the top (3) dust inside the bulb condenses on the top (4) glass undergoes a change due to the heat
Last Answer : dust inside the bulb condenses on the top
Description : Why does an ordinary glass tumbler crack when very hot tea or milk is poured in it?
Last Answer : Answer: When a hot liquid is poured into a tumbler, the inner layer of the tumbler gets heated, it expands before the outer layer and an unequal expansion of both layers causes the tumbler to crack.
Description : During hot weather, the fan produces a feeling of comfort. This is because – (1) fan supplies cool air (2) fan cools the air (3) our perspiration evaporates rapidly (4) conductivity of air increases
Last Answer : (3) our perspiration evaporates rapidly Explanation: Fans make the air more comfortable for two reasons: (1) by moving the air, they blow away body heat and evaporate sweat, cooling the body, and (2) they also mix the cooler air near the floor with the warmer air by people's faces.
Description : Water on heating from 1 to 4°C (A) Contracts (B) Expands (C) Has same volume (D) May contract or expand
Last Answer : (A) Contracts
Description : As water solidifies it does one of the following: w) gives off heat and contracts x) gives off heat and expands y) takes in heat and contracts z) takes in heat and expands
Last Answer : ANSWER: X -- GIVES OFF HEAT AND EXPANDS
Description : The length of a liquid stream while flowing over a weir __________ at the ends of the sill. (A) Expands (B) Does not change (C) Contracts (D) None of these
Last Answer : Answer: Option C
Description : The surface of water in a pond remains cool even on a hot day because 1. water evaporates at the surface and evaporation causes cooling 2. the heat absorbed at the surface is transmitted downwards 3. Water in contact with the bottom ... /are correct? (a) 1 only (b) 3 only (c) 1 and 3 (d) 1, 2 and 3
Last Answer : Ans:(a)
Description : After long periods of use, a gray spot develops on the inside of a bulb. This is because of: A. The tungsten filament evaporates and collects there B. The heat of the bulb scorches the glass at the top C. Dust inside the bulb condenses on the top D. Glass undergoes a change due to the heat
Description : What pattern would be formed if sawdust was sprinkled on the glass instead of iron filings?
Last Answer : No specific pattern, sawdust is a nonmagnetic material.
Description : Take a 250 mL beaker/glass tumbler. Fill half of it with water. Now carefully cut a small piece of sodium metal. Dry it using filter paper and wrap it in a small piece of cotton. Put the sodium piece wrapped in cotton into the beaker. Observe carefully. -Science
Last Answer : On touching the beaker, it was felt hot. The solution turns the red litmus paper to blue which shows it is basic in nature. Blue litmus paper do not show any colour change with the solution.
Description : A student sets up an expirment on photoysthesis as folows : He takes soda water in a glass tumbler and adds chloroplyll into the contents and keeps th
Last Answer : A student sets up an expirment on photoysthesis as folows : He takes soda water in a ... because intact chloroplasts are needed for the process.
Description : Oral neomycin is beneficial in hepatic coma because: A. In hepatic failure patients it is absorbed from the intestines B. It decreases ammonia production by gut bacteria C. It reacts chemically with ... gut to prevent its diffusion into blood D. It induces ammonia detoxifying enzymes in the liver
Last Answer : B. It decreases ammonia production by gut bacteria
Description : Hot coffee is poured simultaneously in four metallic tumblers painted outside with different types of paints. After some time, the coffee will be found coldest in the tumbler painted (a) rough white (b) shining white (c) rough black (d) shining black
Last Answer : Ans:(c)
Description : Pick up the correct statement from the following: (A) The free quartz suddenly expands at a temperature lower than 600°C (B) The lime stone resists fire upto about 800°C and at higher temperature it splits into ... (C) The sand stone with silicates resist a fire in a better way (D) All the above
Last Answer : Answer: Option D
Description : If a fluid expands suddenly into vacuum through an orifice of large dimension, then such a process is called (a) free expansion (b) hyperbolic expansion (c) adiabatic expansion (d) parabolic expansion (e) throttling.
Last Answer : Answer : a
Description : There was a man walking in the desert. It was an especially hot day that day. In the distance, the man suddenly saw a restaurant. He rejoiced and ran to the restaurant and immediately asked the waiter for a ... 's head. The man replied with, "thank you". Why did the man say "thank you"? -Riddles
Last Answer : IT WAS A WATER GUN.
Description : On placing an inverted tumbler over a burning candle, the flame extinguishes after some – time . This is because of non –availability of a) oxygen b)water vapour c)carbon dioxide d)wax
Last Answer : a) oxygen
Description : Let's say we are flying over a large, flat part of Africa. Half of the area is hotter than the other half. The surface pressure is 1000 hPa everywhere. If we fly over at an elevation ... reads the same pressure everywhere. (d) The gauge varies with the latitude and the temperature of the surface.
Last Answer : (a) The cold part.
Description : An egg sinks in soft water but floats in a concentrated solution of salt because – (1) Egg absorbs salt from the solution and expands (2) Albumin dissolves in salt solution and egg becomes lighter (3) The density of salt solution exceeds the density of eggs (4) Water has high surface tension
Last Answer : (3) The density of salt solution exceeds the density of eggs Explanation: Following the density principle, the density of the egg compared to the density of the tap water is lesser (the density principle ... and that is why an egg sinks in soft water but floats in a concentrated solution of salt.
Description : Pipelines in cold countries often burst in winter, because – (1) Water freezes and expands in its volume (2) Temperature of ice is less than that of water (3) Pipelines contract in their volume (4) Pipelines expand due to freezing
Last Answer : (1) Water freezes and expands in its volume Explanation: Water expands on freezing. When liquid water is cooled, it contracts like one would expect until a temperature of approximately 4 degrees ... it expands by approximately 9%. The fact that water expands upon freezing causes icebergs to float.
Description : In severe winter, in cold countries water pipes burst because – (1) Water expands on freezing (2) Contraction of water pipes (3) High atmospheric pressure (4) Combined effect of all the above three
Last Answer : (1) Water expands on freezing Explanation: Most liquids have a quite simple behavior when they are cooled (at a fixed pressure): they shrink. The liquid contract as it is cooled; ... substance solidifies, which causes it to contract some more because crystalline solids are usually tightly packed.
Description : Pipelines in cold countries often burst in winter, because (1) water freezes and expands in its volume (2) temperature of ice is less than that of water (3) pipelines contract in their volume (4) pipelines expand due to freezing
Last Answer : water freezes and expands in its volume
Description : In severe winter, in cold countries water pipes burst because (1) water expands on freezing (2) contraction of water pipes (3) high atmospheric pressure (4) combined effect of all the above three
Last Answer : water expands on freezing
Description : An egg sinks in soft water but floats in a concentrated solution of salt because (1) egg absorbs salt from the solution and expands (2) albumin dissolves in salt solution and egg becomes lighter (3) the density of salt solution exceeds the density of eggs (4) water has high surface tension
Last Answer : the density of salt solution exceeds the density of eggs
Description : Which one of the following statements is incorrect? (a) The competitive inhibitor does not affect the rate of breakdown of the enzyme-substrate complex. (b) The presence of the competitive inhibitor ... . (d) In competitive inhibition, the inhibitor molecule is not chemically changed by the enzyme.
Last Answer : (b) The presence of the competitive inhibitor decreases the Km of the enzyme for the substrate
Description : Pick out the correct statement. (A) In catalytic reactions, the catalyst reacts with the reactants (B) A catalyst initiates a chemical reaction (C) A catalyst lowers the activation energy of ... molecules (D) A catalyst cannot be recovered chemically unchanged at the end of the chemical reaction
Last Answer : (C) A catalyst lowers the activation energy of the reacting molecules
Description : Water is not effective in extinguishing a fire caused by petrol because (1) the flame is too hot for water to cool it down (2) water and petrol react chemically (3) water and petrol are ... 4) water and petrol are immiscible with each other and petrol which forms the upper layer continues to burn
Last Answer : water and petrol are immiscible with each other and petrol which forms the upper layer continues to burn
Description : A gas thermometer is more sensitive than a liquid thermometer because a gas: (1) is lighter than liquid (2) expands more than a liquid (3) is easy to obtain (4) does not change state easily
Last Answer : (4) does not change state easily Explanation: Gas is easily compressed so it would have a more versatile range of measurement at least in our atmospheric conditions. Liquid is not so ... apparatus is a constant volume thermometer. Gas thermometers are often used to calibrate other thermometers.
Description : A gas thermometer is more sensitive than a liquid thermometer because a gas : (1) is lighter than liquid (2) expands more than a liquid (3) is easy to obtain (4) does not change state easily
Last Answer : does not change state easily
Description : What happens to a liquid, when the vapour pressure equals the atmospheric pressure? (1) The liquid cools (2) The liquid boils (3) No change (4) The liquid evaporates
Last Answer : (2) The liquid boils Explanation: Ordinary evaporation is a surface phenomenon -since the vapor pressure is low and since the pressure inside the liquid is equal to atmospheric pressure plus ... pressure is equal to atmospheric pressure, bubbles form, and the vaporization becomes a volume phenomena.
Last Answer : The liquid boils
Description : Plants are killed in winter by frost because (a) No photosynthesis occurs at low temperature (b) Of desiccation (c) Water in the plants freezes (d) Water in the plants evaporates
Last Answer : What to do if the elevator suddenly breaks. 1. Don't try to jump: Many people say that you have to jump when the lift is broken so that the balance of the lift is right with the balance of the ... the legs. 3. When the elevator falls, you should lie down on your back in the middle of the elevator.
Description : When an electric bulb breaks, there is a mild bang due to (a) the chemical reaction between the enclosed gases (b) the compressed gases rushing out suddenly (c) the air rushing in to fill the evacuated space (d) some other unknown reason
Description : Is the liquid propane in a barbecue evaporates away because the user left the valve open a chemical or physical change?
Last Answer : It's a physical change. Chemically, it's still propane - butit's physically changed from a liquid to a gas.
Description : A little ether on the palm gives a cooling sensation because ether (a) is a cold liquid (b) evaporates (c) enters the pores of the skin (d) condenses on the palm
Description : The first step in the generation of a sea breeze is . (a) air over land expands and builds a pressure gradient at the surface that pushes air offshore (b) air over land expands and builds ... forms a cloud (d) air over land expands and builds a pressure gradient aloft that pushes air offshore
Last Answer : air over land expands and builds a pressure gradient aloft that pushes air offshore
Description : Having a brownish coat thickly sprinkled with white or grey -Do You Know?
Last Answer : answer: