Answer:
a) Focal length of the lens is 8 cm which is a convex lens
b) 6 cm
c) The lens is a convex lens and produces a virtual image which is upright and two times larger than the object.
Explanation:
u = Object distance = 4 cm
v = Image distance = -8 cm
f = Focal length
Lens Equation
a) Focal length of the lens is 8 cm which is a convex lens
Magnification
b) Height of image is 2×3 = 6 cm
Since magnification is positive the image upright
c) The lens is a convex lens and produces a virtual image which is upright and two times larger than the object.
Answer:
Explanation:
Let the magnetic field be B = B₁i + B₂j + B₃k
Force = I ( L x B ) , I is current , L is length and B is magnetic field .
In the first case
force = - 2.3 j N
L = 2.5 i
puting the values in the equation above
- 2.3 j = 8 [ 2.5 i x ( B₁i + B₂j + B₃k )]
= - 20 B₃ j + 20 B₂ k
comparing LHS and RHS ,
20B₃ = 2.3
B₃ = .115
B₂ = 0
In the second case
L = 2.5 j
Force = I ( L x B )
2.3i−5.6k = 8 ( 2.5 j x (B₁i + B₂j + B₃k )
= - 20 B₁ k + 20B₃ i
2.3i−5.6k = - 20 B₁ k + 20B₃ i
B₃ = .115
B₁ = .28
So magnetic field B = .28 i + .115 B₃
Part A
x component of B = .28 T
Part B
y component of B = 0
Part C
z component of B = .115 T .
Answer:
The distance of separation is 
Explanation:
The mass of the each ball is 
The negative charge on each ball is 
Now we are told that the lower ball is restrained from moving this implies that the net force acting on it is zero
Hence the gravitational force acting on the lower ball is equivalent to the electrostatic force i.e
=> 
here k the the coulomb's constant with a value 
So
![0.01 * 9.8 = \frac{ 9*10^9 *[1*10^{-6} * 1*10^{-6}]}{d}](https://tex.z-dn.net/?f=0.01%20%2A%209.8%20%20%3D%20%20%5Cfrac%7B%209%2A10%5E9%20%2A%5B1%2A10%5E%7B-6%7D%20%2A%201%2A10%5E%7B-6%7D%5D%7D%7Bd%7D)
A photoelectric cell is an electronic device which is used to convert light energy into electric energy.The operation of this device is based on photoelectric effect.
Light of suitable frequency i.e greater or equal to threshold frequency will fall on the cathode maintained at negative potential.The electron emission will take place and these electrons are drifted towards the anode which is at positive potential.
Here,only those radiations will be capable of emitting electrons irrespective of surface barrier of metals whose energy is greater than the work function.
We know that the radiation having long wavelength has least energy as energy and wavelength are inversely proportional to each other.
Here h is the Planck's constant,c is the velocity of light.
Here we have been given red light and blue light.
In the visible spectrum of radiation, the red light has longer wavelength than all other colors of light.Hence blue light has more energy as it's wavelength is less as compared to red light.
Hence, the blue light will activate the most and red the least.
Answer:d
Explanation:
Spring is compressed to a distance of x from its equilibrium position
Work done by block on the spring is equal to change in elastic potential energy
i.e. Work done by block 
therefore spring will also done an equal opposite amount of work on the block in the absence of external force
Thus work done by spring on the block 
Thus option d is correct
