Physics-
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
- 5 cm
- 2 cm
- 25 mm
- 0.1 mm
Answer:The correct answer is: 5 cm
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maths-
The differential equation of all circles which pass through the origin and whose centres lie on y-axis is
The differential equation of all circles which pass through the origin and whose centres lie on y-axis is
maths-General
maths-
Let p, q
{1,2,3,4}.Then number of equation of the form px2+qx+1=0,having real roots ,is
q2–4p
0
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
q=3
q=4
Hence 7 values of (p, q)7equationsarepossible.
Let p, q
{1,2,3,4}.Then number of equation of the form px2+qx+1=0,having real roots ,is
maths-General
q2–4p
0
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
q=3
q=4
Hence 7 values of (p, q)7equationsarepossible.
maths-
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
p2 – 5p + 4 = 0
p – p2 = 0
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
p2 – 5p + 4 = 0
p – p2 = 0
For (i), (ii) & (iii) to hold simultaneously p = 1.
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
maths-
If
then the solution of the equation is :
If
then the solution of the equation is :
maths-General
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
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
Given,
Comparing Eqs. (i) and (ii), we get
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
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
Given,
Comparing Eqs. (i) and (ii), we get
maths-
The degree of the differential equation satisfying
is
The degree of the differential equation satisfying
is
maths-General
physics-
Maximum kinetic energy (Ek ) of a photoelectron varies with the frequency ( v ) of the incident radiation as

Maximum kinetic energy (Ek ) of a photoelectron varies with the frequency ( v ) of the incident radiation as

physics-General
maths-
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)=
maths-General
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
maths-
If f(x) = ax2+ bx + c such that f(p) + f(q) = 0 where a
0 ; p , q
R then number of real roots of equation f(x) = 0in interval [p, q] is
f(p)=–f(q)
eitherf(p)f(q)<0 or f(p) =0=f(q)
exactlyonerootin(p,q) orrootsarepandq
If f(x) = ax2+ bx + c such that f(p) + f(q) = 0 where a
0 ; p , q
R then number of real roots of equation f(x) = 0in interval [p, q] is
maths-General
f(p)=–f(q)
eitherf(p)f(q)<0 or f(p) =0=f(q)
exactlyonerootin(p,q) orrootsarepandq
maths-
If f(x) is a polynomial of degree five with leading coefficient one such that f(1)=12,f(2)=22,f(3)=32,f(4)=42,f(5)=52 then
If f(x) is a polynomial of degree five with leading coefficient one such that f(1)=12,f(2)=22,f(3)=32,f(4)=42,f(5)=52 then
maths-General
physics-
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
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
physics-General
physics-
Lux is equal to
Lux is equal to
physics-General
physics-
Five lumen/watt is the luminous efficiency of a lamp and its luminous intensity is 35 candela. The power of the lamp is
Efficiency of light source
..... (i)
and
..... (ii)
From equation (i) and (ii)
.
and
From equation (i) and (ii)
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)
and
..... (ii)
From equation (i) and (ii)
.
and
From equation (i) and (ii)