1 ) What type of image of an object is formed by a convex lens , when that object is placed beyond the focal length ?
A ) Diminished , B ) Inverted ,
C ) Real , D ) All of these ,
Correct
Answer : - D ) All of these ,
2 )
An object gets closer to the focal point of converging lens from infinity , so
its image size : -
A ) Increase , B
) Decrease ,
C ) Not effected , D
) None of these ,
Correct
Answer : - A ) Increase ,
3 )
Convex lens acts as a magnifying glass , when object is placed btw lens and its
focal point F , So what type of image will be formed : -
A ) Virtual , B
) Erect ,
C ) Enlarged , D
) All of these ,
Correct
Answer : - D ) All of these ,
Magnifying power is inversely proportional to focal
length .
Formula of magnifying power of magnifying glass : -
M =
1 + (d/f) .
4 )
A convex lens behaves as a concave lens and vice versa , when placed in a
liquid of refractive index ………… refractive index of lens .
A ) Greater than , B
) Smaller than ,
C ) Equalls to , D
) None of these ,
Correct
Answer : - A ) Greater than ,
5 ) Windshield
wipers of car works according to charging and discharging of ……. ?
A ) Resistor , B
) Inductor ,
C ) Capacitor , D
) None of these ,
Correct
Answer : - C ) Capacitor ,
6 )
In Millikan’s oil drop experiment , ………………… are used .
A ) Parallel plate capacitor , B ) Coils ,
C ) Solenoid Inductor , D ) None of these ,
Correct
Answer : - A ) Parallel plate capacitor
,
7 )
A charge q is placed at the centre of a cube . The electric flux through the
one face is 1/6th of total
flux passing through cube . So the total electric flux of a cube : -
A ) Φ = q / (E˳) , B ) Φ =
q / (6E˳) ,
C ) Φ = q / (3E˳)
, D
) None of these ,
Correct
Answer : - A ) Φ = q / (E˳) ,
Solution
: -
Formula
: -
We
have formula for electric flux : - Φ =
q / (E˳) ,
So , for each face (1/6th) of a cube : - Φ = q / (6E˳)
,
So electric flux of whole cube (6 faces) : -
Φ = 6 * {q / (6E˳) } ,
Φ = 6q / (6E˳) ,
Φ =
q / (E˳) , Answer .
8 )
In young double slit experiment (YDSE) , if we use red light instead of blue ,
then fringe spacing will …….. ?
A ) increase , B
) Decrease ,
C ) No change , D
) None of these ,
Correct
Answer : - A ) increase ,
Because fringe spacing formula : - y =
(Lλ)/d ,
So fringe spacing is directly related to wavelength ,
And red light has greater
wavelength then blue .
Wavelength and frequency of different waves increasing as
shown : -
9 ) A
positive (+ve) charge is moving upwards vertically . It enters a magnetic field directed to the
north . The force on the charge will be
towards …….. : -
A ) North , B
) South ,
C ) East , D
) West ,
Correct
Answer : - D ) West ,
Explanation
: -
Here we use Flemings left hand rule : - Thumb shows force , first finger shows magnetic field and middle finger shows
current .
So if middle finger is towards vertically upwards and
first finger is towards north , So force would be in direction of west .
10 )
A galvanometer acting as a voltmeter
will have high resistance in ……… with its coil.
A ) Series , B
) Parallel ,
C ) Both of these , D
) None of these ,
Correct Answer : -
A ) Series ,
11
) A galvanometer can be converted to a
ammeter by connecting a shunt resistance in ……… with its coil.
A ) Series , B
) Parallel ,
C ) Both of these , D
) None of these ,
Correct
Answer : - B ) Parallel ,
12 )
The direction of magnetic flux flow is from ……….. ,
A ) North pole to north pole , B ) South pole to north pole ,
C ) North pole to south pole , D ) South pole to south pole ,
Correct
Answer : - C ) North pole to south pole
,
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