Increased by a factor of 4
        
             
        
        
        
Answer:
Telescope
Explanation:
Telescope is usually defined as an optical instrument that is commonly used to observe the objects in a magnified way that are located at a large distance from earth. These telescopes are comprised of lenses and curved mirrors that are needed to be arranged in a proper way in order to have a prominent look. It is commonly used by the astronomers.
This was first constructed by Hans Lippershey in the year 1608.
 
        
             
        
        
        
Answer:
A.2.95 m
B.7
Explanation:
We are given that 
Diffraction grating=600 lines/mm
d=
Wavelength of light,
l=4.6 m
A.We have to find the distance between the two m=1 bright fringes

For first bright fringe, =1


The distance between two m=1 fringes

Hence, the distance between two m=1 fringes=2.95 m
B.For maximum number of fringes,


Substitute the values 


Maximum number of bright fringes on the scree=
 
        
             
        
        
        
Answer:
Explanation:
Let the charge on bead A be q nC  and the charge on bead B be 28nC - qnC
Force F between them 
4.8\times10^{-4} = 
=120 x 10⁻⁸ = 9 x q(28 - q ) x 10⁻⁹
133.33 = 28q - q²
q²- 28q +133.33 = 0 
It is a quadratic equation , which has two solution 
q_A = 21.91 x 10⁻⁹C or q_B = 6.09 x 10⁻⁹ C
 
        
             
        
        
        
Answer
Given,
Length of the wire,L = 31 cm = 0.31 m
mass of the wire, m = 9 g = 0.009 Kg
Current in the wire,I = 7 A
Magnetic field strength, B= ?
Equating magnetic force to the weight of the wire.
 
 
 
B = 0.0407 T
For Force to be upward magnetic field direction should be outward of the plane of paper.