Physics-

#### 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

Physics-General

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#### Answer:The correct answer is: 1According 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

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### Related Questions to study

maths-

#### Statement-1- The number is not divisible by 11.Because

Statement-2- If p is a prime, the exponent of p in n! is + + +……Where [x] denotes the greatest integer x.

#### Statement-1- The number is not divisible by 11.Because

Statement-2- If p is a prime, the exponent of p in n! is + + +……Where [x] denotes the greatest integer x.

maths-General

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

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

maths-General

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#### Number of values of 'p' for which the equation possess more than two roots ,is:

For (p2– 3p+2)x2–(p2–5p+4)x+p–p2=0tobe anidentity

p2–3p+2 =0 p = 1, 2...(i)

p2 – 5p + 4 = 0 p = 1, 4...(ii)

p – p2 = 0 p = 0, 1...(iii)

For (i), (ii) & (iii) to hold simultaneously p = 1.

p2–3p+2 =0 p = 1, 2...(i)

p2 – 5p + 4 = 0 p = 1, 4...(ii)

p – p2 = 0 p = 0, 1...(iii)

For (i), (ii) & (iii) to hold simultaneously p = 1.

#### Number of values of 'p' for which the equation possess more than two roots ,is:

maths-General

For (p2– 3p+2)x2–(p2–5p+4)x+p–p2=0tobe anidentity

p2–3p+2 =0 p = 1, 2...(i)

p2 – 5p + 4 = 0 p = 1, 4...(ii)

p – p2 = 0 p = 0, 1...(iii)

For (i), (ii) & (iii) to hold simultaneously p = 1.

p2–3p+2 =0 p = 1, 2...(i)

p2 – 5p + 4 = 0 p = 1, 4...(ii)

p – p2 = 0 p = 0, 1...(iii)

For (i), (ii) & (iii) to hold simultaneously p = 1.

maths-

#### Let p, q{1,2,3,4}.Then number of equation of the form px^{2}+qx+1=0,having real roots ,is

q2–4p0

q=2 p=1

q=3 p=1,2

q=4 p=1,2,3,4

Hence 7 values of (p, q)7equationsarepossible.

q=2 p=1

q=3 p=1,2

q=4 p=1,2,3,4

Hence 7 values of (p, q)7equationsarepossible.

#### Let p, q{1,2,3,4}.Then number of equation of the form px^{2}+qx+1=0,having real roots ,is

maths-General

q2–4p0

q=2 p=1

q=3 p=1,2

q=4 p=1,2,3,4

Hence 7 values of (p, q)7equationsarepossible.

q=2 p=1

q=3 p=1,2

q=4 p=1,2,3,4

Hence 7 values of (p, q)7equationsarepossible.

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The differential equation of all circles which pass through the origin and whose centres lie on y-axis is

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#### A simple magnifying lens is used in such a way that an image is formed at 25 *cm* away from the eye. In order to have 10 *times* magnification, the focal length of the lens should be

or

#### A simple magnifying lens is used in such a way that an image is formed at 25 *cm* away from the eye. In order to have 10 *times* magnification, the focal length of the lens should be

physics-General

or

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#### If then the solution of the equation is :

#### If then the solution of the equation is :

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#### The degree of the differential equation satisfying is

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#### Maximum kinetic energy (E_{k} ) of a photoelectron varies with the frequency ( v ) of the incident radiation as

#### Maximum kinetic energy (E_{k} ) of a photoelectron varies with the frequency ( v ) of the incident radiation as

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#### If f(x) is a differentiable function satisfying f(x+ y)= f(x)f(y) x, y R and f'(0)=2 then f(x)=

#### If f(x) is a differentiable function satisfying f(x+ y)= f(x)f(y) x, y R and f'(0)=2 then f(x)=

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#### If f(x) = ax^{2}+ bx + c such that f(p) + f(q) = 0 where a0 ; p , qR then number of real roots of equation f(x) = 0in interval [p, q] is

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exactlyonerootin(p,q) orrootsarepandq

exactlyonerootin(p,q) orrootsarepandq

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exactlyonerootin(p,q) orrootsarepandq

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#### If f(x) is a polynomial of degree five with leading coefficient one such that f(1)=1^{2},f(2)=2^{2},f(3)=3^{2},f(4)=4^{2},f(5)=5^{2} then

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#### A 60 *watt* bulb is hung over the center of a table at a height of 3 *m*. The ratio of the intensities of illumination at a point on the centre of the edge and on the corner of the table is

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#### Five lumen/watt is the luminous efficiency of a lamp and its luminous intensity is 35 candela. The power of the lamp is

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..... (i)

and ..... (ii)

From equation (i) and (ii)

.

..... (i)

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From equation (i) and (ii)

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#### Five lumen/watt is the luminous efficiency of a lamp and its luminous intensity is 35 candela. The power of the lamp is

physics-General

Efficiency of light source

..... (i)

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From equation (i) and (ii)

.

..... (i)

and ..... (ii)

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.