Tag: temperature and heat

Quizzes (15) Questions (111)

Questions Related to temperature and heat

Multiple choice physics temperature and heat modes of heat transfer - conduction conduction heat and modes of heat transfer

Two rods of equal length and area of cross-sectional are kept parallel and lagged between temperature $ 20^o C and 80^oC $ The ration of the effective thermal conductivity to that of the first rod is
 $ \left[ the\quad ration\left( \frac { K _ 1 }{ K _ 2 }  \right) =\frac { 3 }{ 4 }  \right]  $

  1. 7 : 4

  2. 7 : 6

  3. 4 : 7

  4. 7 : 8
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice physics temperature and heat modes of heat transfer - conduction conduction heat and modes of heat transfer

Fix a lighted candle on a table. Put a glass chimney over the candle in such a way that air can enter the chimney from below. What happens to the flame? 

  1. Continues burning

  2. Flickers off

  3. Flickers off and give smoke

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When a chimney is placed over a candle, the air supply is restricted. The lack of sufficient oxygen leads to incomplete combustion, which produces soot (smoke) and causes the flame to become unstable or flicker.

Multiple choice physics temperature and heat modes of heat transfer - conduction conduction heat and modes of heat transfer

Two spheres of different materials one with double the radius and one - fourth wall thickness of the other, are filled with $r$ ice. If the time taken for complete melting ice in the large radius one is $25 minutes$ and that for smaller one is $16 minutes$, $r$ the ratio of thermal conductivity of the materials of larger sphere to the smaller sphere is $r$

  1. $4:5$

  2. $5:4$

  3. $25:1$

  4. $1:25$
Reveal answer Fill a bubble to check yourself
D Correct answer
Multiple choice physics temperature and heat modes of heat transfer - conduction conduction heat and modes of heat transfer

At a common temperature ,a block of wood and a block of metal feel equally cool or hot. The temperatures of metal and wood are

  1. $Less$ $than$ $the$ $temperature$ $of$ $the$ $body$

  2. $Equal$ $than$ $the$ $temperature$ $of$ $the$ $body$

  3. $Greater$ $than$ $the$ $temperature$ $of$ $the$ $body$

  4. $Either$ $(a)$ $or$ $(c)$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When objects are at the same temperature as the surroundings, they feel different because of their thermal conductivity. Metal conducts heat away from the hand faster than wood, making it feel colder, even though they are at the same temperature.

Multiple choice physics temperature and heat modes of heat transfer - conduction conduction heat and modes of heat transfer

Choose the correct experiment to demonstrate the transfer of heat by the process of conduction.

  1. <span>Take two metal blocks of same size &amp; shape and heat one of them to a considerable temperature, then allow both the blocks to touch each other, after a while, you will see the other block gets heated due to contact.</span>

  2. <span>Take two metal blocks of same size &amp; shape and heat one of them to a considerable temperature, then keep the blocks separate, after a while you will see the other block gets heated due to contact.</span>

  3. <span>Take two metal blocks of same size &amp; shape and heat one of them to a considerable temperature, then allow both the blocks to touch each other after the block get cooled down, after a while you will see the other block gets heated due to contact.</span>

  4. None of above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Take two metal blocks of same size & shape and heat one of them to a considerable temperature, then allow both the blocks to touch each other, after a while you will see the other block gets heated due to contact.

Multiple choice physics temperature and heat modes of heat transfer - conduction conduction heat and modes of heat transfer

If a rod is in a variable state (not in steady state), then

  1. Temperature gradient remains constant

  2. Temperature of rod is function of time and distance from one of end

  3. Temperature of rod is only function of distance from one of end

  4. Temperature of rod is only function of time
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In a variable state (non-steady state), the temperature at any point in the rod changes with time as heat is absorbed by the material to change its internal energy. Therefore, temperature is a function of both position and time.

Multiple choice physics temperature and heat modes of heat transfer - conduction conduction heat and modes of heat transfer

State true or false:
The more is the temperature difference of hot and cold body more slowly the heat flows from it into the cold body

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The amount of heat leaving the hot object will be equal to the amount of heat received by the colder object (assuming nothing else is around to receive some of the heat). The rate at which heat transfers from the hotter object to the colder object increases with the temperature difference between the objects.
Multiple choice physics temperature and heat modes of heat transfer - conduction conduction heat and modes of heat transfer

By which of the following methods could a cup of hot tea lose heat when placed on metallic table in a class room
a) conduction
b) convection
c) radiation
d) evaporation of liquid.

  1. a, b

  2. b,c

  3. a,b,c

  4. a,b,c,d
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Conduction occurs through the walls of the cup.
Radiation occurs from the top surface.
Convection occurs at the top of the cup.
Evaporation of liquid also occurs.

Multiple choice physics temperature and heat modes of heat transfer - conduction conduction heat and modes of heat transfer

The quantity of heat flowing for $10 \ s$ through a rod of length $40\ cm$, area $50 \ cm^{2}$ is $200\ J$. If the temperature difference at the ends of the rod is 80$^{o}$C , the coefficient of thermal conductivity of the rod in Wm$^{-1}$K$^{-1}$ is:

  1. $20$

  2. $60$

  3. $80$

  4. $120$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$Q = 200$
$A = 50 \times 10^{-4}\ m^2$
${\theta}^{} _{1} = 80^\circ C    ;   \ \ {\theta}^{} _{2} = 0$
$t = 10\ s ; \ \    l  = 0.40\ m$
$Q = \dfrac{KA\Delta T t}{L}$
$200 = \dfrac{K  \times 50\times 10^{-4}\times    80\times    10}{0.4}$ 
$K = 20\ W/mK$