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 ,

 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 1/6^th  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 (1/6^th) 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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