PHYSICS [1 Mark Question Answer]

A newly made quilt is warmer than an old one because the cotton in the old quilt gets compressed and very little air will remain trapped in it, hence heat insulation is quite poor.

We wear woolen clothes in winter because woolen clothes have tiny pores and air is trapped in these pores and being a bad conductor, the trapped air obstructs the flow of body heat to the surroundings.

No, conduction is not possible in vacuum.

Temperature is the degree of hotness or coldness of a body compared to other bodies around it. SI unit of temperature is Kelvin (K)

Heat is defined as a form of energy which flows from one point to another on account of temperature difference.

No, the conduction is not possible in gases. Gases are bad conductors.

Factors affecting evaporation are
(a). Humidity- more the humidity less is the evaporation
(b). surface area- more the surface area more is the evaporation
(c). wind- more the wind more is the evaporation
(d). temperature- more the temperature more is the evaporation

Evaporation is the phenomenon of a change of a liquid into vapour without raising the temperature. Evaporation needs energy for phase change from liquid to gases. As water evaporates off your skin, it absorbs energy(heat) from the body to make the phase change to gas thus cooling the body.

Yes, because the heat flow is only due to temperature difference between the temperature of two bodies.

Telephone wires sag in summer because due to heat of the sun, the wire expands and increases in length, thus they sag in summer.

No, the exact relation is as given
1 calorie = 4.2 joules.

Two uses of bimetallic strip are
(a). As thermostat in electric iron
(b). As balance wheel in watches

Calorie. Because 1 calorie = 4.2 joules.

Heat changes the temperature of a body due to flow of heat in or out of the given body.

According to principle of calorimetry of mixtures,
Heat gained = Heat lost

Yes, heat is the cause of temperature because temperature of a body rises when the heat flows into the body.