Physics-

General

Easy

Question

# According to Newton’s law of cooling, the rate of cooling is proportional to , where is the temperature differences between the body and the surroundings and is equal to

- 3
- 2
- 4
- 1

## The correct answer is: 1

### According to Newton’s law of cooling the rate of loss of heat of a body is directly proportional to the difference in temperature of the body,

(i)

Given, (ii)

Comparing Eqs. (i) and (ii), we get

=1

### Related Questions to study

Maths-

### satisfies the relation then value of A and B respectively are:

### satisfies the relation then value of A and B respectively are:

Maths-General

physics-

### Radius of a conductor increases uniformly from left end to right end as shown in fig Material of the conductor is isotropic and its curved surface is thermally insulated from surrounding. Its ends are maintained at temperatures and : If, in steady state, heat flow rate is equal to , then which of the following graphs is correct

Since the curved surface of the conductor is thermally insulated, therefore, in steady state, the rate of flow of heat at every section will be the same. Hence the curve between and will be straight line parallel to -axis

### Radius of a conductor increases uniformly from left end to right end as shown in fig Material of the conductor is isotropic and its curved surface is thermally insulated from surrounding. Its ends are maintained at temperatures and : If, in steady state, heat flow rate is equal to , then which of the following graphs is correct

physics-General

Since the curved surface of the conductor is thermally insulated, therefore, in steady state, the rate of flow of heat at every section will be the same. Hence the curve between and will be straight line parallel to -axis

physics-

### Water and turpentine oil (specific heat less than that of water) are both heated to same temperature. Equal amounts of these placed in identical calorimeters are then left in air

As we know, Rate of cooling

It is clear that, at a particular time after start cooling, temperature of oil will be less than that of water

So graph represents the cooling curve of oil and represents the cooling curve of water

It is clear that, at a particular time after start cooling, temperature of oil will be less than that of water

So graph represents the cooling curve of oil and represents the cooling curve of water

### Water and turpentine oil (specific heat less than that of water) are both heated to same temperature. Equal amounts of these placed in identical calorimeters are then left in air

physics-General

As we know, Rate of cooling

It is clear that, at a particular time after start cooling, temperature of oil will be less than that of water

So graph represents the cooling curve of oil and represents the cooling curve of water

It is clear that, at a particular time after start cooling, temperature of oil will be less than that of water

So graph represents the cooling curve of oil and represents the cooling curve of water

physics-

### Variation of radiant energy emitted by sun, filament of tungsten lamp and welding are as a function of its wavelength is shown in figure. Which of the following option is the correct match?

From the graph

Temperature of sun will be maximum

### Variation of radiant energy emitted by sun, filament of tungsten lamp and welding are as a function of its wavelength is shown in figure. Which of the following option is the correct match?

physics-General

From the graph

Temperature of sun will be maximum

physics-

### Six identical metallic rods are joined together in a pattern as shown in the figure. Points A and D are maintained at temperature and . The temperature of the junction will be

(i)

(ii)

Solving (i) and (ii)

### Six identical metallic rods are joined together in a pattern as shown in the figure. Points A and D are maintained at temperature and . The temperature of the junction will be

physics-General

(i)

(ii)

Solving (i) and (ii)

physics-

### Which curve shows the rise of temperature with the amount of heat supplied, for a piece of ice?

Initially on heating temperature rises from (200K) to 0(273K). Then ice melts and temperature does not rise. After the whole ice has melted, temperature begins to rise until it reaches 100 (373K). Then it becomes constant and after that it changes to vapours.

### Which curve shows the rise of temperature with the amount of heat supplied, for a piece of ice?

physics-General

Initially on heating temperature rises from (200K) to 0(273K). Then ice melts and temperature does not rise. After the whole ice has melted, temperature begins to rise until it reaches 100 (373K). Then it becomes constant and after that it changes to vapours.

physics-

### The graph signifies

### The graph signifies

physics-General

physics-

### The figure given below shows the cooling curve of pure wax material after heating. It cools from to and solidifies along If and are respective values of latent heat and the specific heat of the liquid wax, the ratio is

Let the quantity of heat supplied per minute be Then quantity of heat supplied in

In heat supplied

In heat supplied

### The figure given below shows the cooling curve of pure wax material after heating. It cools from to and solidifies along If and are respective values of latent heat and the specific heat of the liquid wax, the ratio is

physics-General

Let the quantity of heat supplied per minute be Then quantity of heat supplied in

In heat supplied

In heat supplied

physics-

### One end of a thermally insulated rod is kept at a temperature and other at . The rod is composed of two sections of lengths and and thermal conductivities and respectively. The temperature at the interface of the two sections is

Let temperature at the interface is T.

For part AB,

For part

At equilibrium,

For part AB,

For part

At equilibrium,

### One end of a thermally insulated rod is kept at a temperature and other at . The rod is composed of two sections of lengths and and thermal conductivities and respectively. The temperature at the interface of the two sections is

physics-General

Let temperature at the interface is T.

For part AB,

For part

At equilibrium,

For part AB,

For part

At equilibrium,

maths-

### If and theperiod of is , then

### If and theperiod of is , then

maths-General

physics-

### The adjoining diagram shows the spectral energy density distribution of a black body at two different temperatures. If the areas under the curves are in the ratio 16 : 1, the value of temperature is

[Given]

Area under curve represents the emissive power of body and emissive power

Area under curve represents the emissive power of body and emissive power

### The adjoining diagram shows the spectral energy density distribution of a black body at two different temperatures. If the areas under the curves are in the ratio 16 : 1, the value of temperature is

physics-General

[Given]

Area under curve represents the emissive power of body and emissive power

Area under curve represents the emissive power of body and emissive power

physics-

### Five identical rods are joined as shown in figure. Point and are maintained at temperature and respectively. The temperature of junction will be

If thermal resistance of each rod is considered then, the given combination can be redrawn as follows

### Five identical rods are joined as shown in figure. Point and are maintained at temperature and respectively. The temperature of junction will be

physics-General

If thermal resistance of each rod is considered then, the given combination can be redrawn as follows

Maths-

### If , then _______________

### If , then _______________

Maths-General

physics-

### Which one of the following is graph for perfectly black body? is the frequency of radiation with maximum intensity, is the absolute temperature.

Intensity is directly proportional to energy.

### Which one of the following is graph for perfectly black body? is the frequency of radiation with maximum intensity, is the absolute temperature.

physics-General

Intensity is directly proportional to energy.

physics-

### Three rods made of same material and having same cross-section are joined as shown in the figure. Each rod is of same length. The temperature at the junction of the three rods is

Let the temperature of function be , then

Or

Or

Or

Or

Or

Or

Or

Or

### Three rods made of same material and having same cross-section are joined as shown in the figure. Each rod is of same length. The temperature at the junction of the three rods is

physics-General

Let the temperature of function be , then

Or

Or

Or

Or

Or

Or

Or

Or