(a) Water at room temperature is a liquid because its freezing point is 0°C and boiling point is 100°C. (b) An iron almirah is a solid at room temperature because melting point of iron is higher than room temperature.
(a) Water at room temperature is a liquid because its freezing point is 0°C and boiling point is 100°C.
(b) An iron almirah is a solid at room temperature because melting point of iron is higher than room temperature.
(a) Naphthalene balls disappear with time without leaving any solid, because naphthalene balls sublime and directly changes into vapour state without leaving any solid. (b) We can get the smell of perfume sitting several metres away because perfume contain volatile solvent and diffuse faster and canRead more
(a) Naphthalene balls disappear with time without leaving any solid, because naphthalene balls sublime and directly changes into vapour state without leaving any solid.
(b) We can get the smell of perfume sitting several metres away because perfume contain volatile solvent and diffuse faster and can reach people sitting several metres away.
We should wear light coloured cotton clothes in summer. Light colour because it reflects heat. Cotton clothes because it has pores in it, which absorbs sweat and allows the sweat to evaporate faster thereby giving cooling effect.
We should wear light coloured cotton clothes in summer. Light colour because it reflects heat. Cotton clothes because it has pores in it, which absorbs sweat and allows the sweat to evaporate faster thereby giving cooling effect.
Tea in a saucer has larger surface area than in a cup. The rate of evaporation is faster with increased surface area. The cooling of tea in saucer takes place sooner than in a cup. Hence we are able to sip hot tea or milk faster from a saucer rather than a cup.
Tea in a saucer has larger surface area than in a cup. The rate of evaporation is faster with increased surface area. The cooling of tea in saucer takes place sooner than in a cup. Hence we are able to sip hot tea or milk faster from a saucer rather than a cup.
The earthen pot is porous with lot of pores on it, the water oozes out through these pores and the water gets evaporated at the surface of the pot thereby causing cooling effect. This makes the pot cold and the water inside the pot cools by this process.
The earthen pot is porous with lot of pores on it, the water oozes out through these pores and the water gets evaporated at the surface of the pot thereby causing cooling effect. This makes the pot cold and the water inside the pot cools by this process.
Give two reasons to justify: (a) water at room temperature is a liquid. (b) an iron almirah is a solid at room temperature.
(a) Water at room temperature is a liquid because its freezing point is 0°C and boiling point is 100°C. (b) An iron almirah is a solid at room temperature because melting point of iron is higher than room temperature.
(a) Water at room temperature is a liquid because its freezing point is 0°C and boiling point is 100°C.
See less(b) An iron almirah is a solid at room temperature because melting point of iron is higher than room temperature.
What is the physical state of water at the following temperature?
(a) 25°C is liquid (b) 0°C is solid or liquid (c) 100°C is liquid and gas
(a) 25°C is liquid (b) 0°C is solid or liquid
See less(c) 100°C is liquid and gas
Arrange the following substances in increasing order of forces of attraction between the particles
Oxygen —> water —> sugar.
Oxygen —> water —> sugar.
See lessGive reason for the following observations. (a) Naphthalene balls disappear with time without leaving any solid. (b) We can get the smell of perfume sitting several meters away.
(a) Naphthalene balls disappear with time without leaving any solid, because naphthalene balls sublime and directly changes into vapour state without leaving any solid. (b) We can get the smell of perfume sitting several metres away because perfume contain volatile solvent and diffuse faster and canRead more
(a) Naphthalene balls disappear with time without leaving any solid, because naphthalene balls sublime and directly changes into vapour state without leaving any solid.
See less(b) We can get the smell of perfume sitting several metres away because perfume contain volatile solvent and diffuse faster and can reach people sitting several metres away.
Convert the following temperatures to the Kelvin scale.
(a) 25°C into K 25 + 273 = 298 K (b) 373°C into K 4 373 + 273 = 646 K
(a) 25°C into K
See less25 + 273 = 298 K
(b) 373°C into K 4 373 + 273 = 646 K
Convert the following temperatures to the Celsius scale.
(a) 293 K into °C 293 – 273 = 20°C (b) 470 K into °C 470 – 273 = 197°C
(a) 293 K into °C
293 – 273 = 20°C
(b) 470 K into °C
470 – 273 = 197°C
See lessWhat type of clothes should we wear in summer?
We should wear light coloured cotton clothes in summer. Light colour because it reflects heat. Cotton clothes because it has pores in it, which absorbs sweat and allows the sweat to evaporate faster thereby giving cooling effect.
We should wear light coloured cotton clothes in summer. Light colour because it reflects heat. Cotton clothes because it has pores in it, which absorbs sweat and allows the sweat to evaporate faster thereby giving cooling effect.
See lessWhy are we able to sip hot tea or milk faster from a saucer rather than a cup?
Tea in a saucer has larger surface area than in a cup. The rate of evaporation is faster with increased surface area. The cooling of tea in saucer takes place sooner than in a cup. Hence we are able to sip hot tea or milk faster from a saucer rather than a cup.
Tea in a saucer has larger surface area than in a cup. The rate of evaporation is faster with increased surface area. The cooling of tea in saucer takes place sooner than in a cup. Hence we are able to sip hot tea or milk faster from a saucer rather than a cup.
See lessWhy does our palm feel cold when we put some acetone or petrol or perfume on it?
Acetone, petrol or perfume evaporate when they come into contact with air. The evaporation causes cooling sensation in our hands.
Acetone, petrol or perfume evaporate when they come into contact with air. The evaporation causes cooling sensation in our hands.
See lessHow does the water kept in an earthen pot (matka) become cool during summer?
The earthen pot is porous with lot of pores on it, the water oozes out through these pores and the water gets evaporated at the surface of the pot thereby causing cooling effect. This makes the pot cold and the water inside the pot cools by this process.
The earthen pot is porous with lot of pores on it, the water oozes out through these pores and the water gets evaporated at the surface of the pot thereby causing cooling effect. This makes the pot cold and the water inside the pot cools by this process.
See less