Physics MCQs thread.

[Zishi]

this one i dint undrstood it completely

First, is the answer D?

 

[hassam]

yes

 

[Hateexams93]

HELP

 

[hassam]

there is one forward force in horizontal direction and one normal force so ans is B

 

[Zishi]

yes

Ok so first of all fringe separation, x, is only changed by things in this formula; x= λD/a

This eliminates three of the options. Light will somehow bend towards bottom when passing through that glass, so fringe pattern will shift to bottom.

 

[Hateexams93]

why its forward ?i thought the friction force will act in opposite direction , as it says total force exerted by the road

 

[hassam]

U MEAN LIGHT WILL GET DIFFRACTED AT THAT EDGE OF GLASS RYT.....?

 

[hassam]

see direction of revolution of tyre

 

[Hateexams93]

ohh..lol ..i guess physics is not for girls ...anyways thanx))))

 

[Hateexams93]

A narrow beam of monochromatic light is incident normally on a diffraction grating. Third-order
diffracted beams are formed at angles of 45
o to the original direction.
What is the highest order of diffracted beam produced by this grating?
A 3rd B 4th C 5th D 6th
HOW TO SOLVE THIS ?

 

[hassam]

32 The filament of a 240 V, 100 W electric lamp heats up from room temperature to its operating
temperature. As it heats up, its resistance increases by a factor of 16.
What is the resistance of this lamp at room temperature?
A 36 Ω B 580 Ω C 1.5 kΩ D 9.2 kΩ
does this factor of 16 means 1/16...i am cnfused cos at the same time he says resistance has increased

 

[Zishi]

U MEAN LIGHT WILL GET DIFFRACTED AT THAT EDGE OF GLASS RYT.....?

I don't know if "diffraction" is proper word to use, but what I can safely say is that it bends.

 

[Zishi]

32 The filament of a 240 V, 100 W electric lamp heats up from room temperature to its operating
temperature. As it heats up, its resistance increases by a factor of 16.
What is the resistance of this lamp at room temperature?
A 36 Ω B 580 Ω C 1.5 kΩ D 9.2 kΩ
does this factor of 16 means 1/16...i am cnfused cos at the same time he says resistance has increased

The operating values of power and voltage are the values when it heats up. At that time its resistance = 576 ohms, and at room temperature it's 16 times this value, s0 576/16 = 36 ohm. A must be the answer.

 

[Hateexams93]

A narrow beam of monochromatic light is incident normally on a diffraction grating. Third-order
diffracted beams are formed at angles of 45
o to the original direction.
What is the highest order of diffracted beam produced by this grating?
A 3rd B 4th C 5th D 6th
HOW TO SOLVE THIS ? ?????????

 

[Zishi]

A narrow beam of monochromatic light is incident normally on a diffraction grating. Third-order
diffracted beams are formed at angles of 45
o to the original direction.
What is the highest order of diffracted beam produced by this grating?
A 3rd B 4th C 5th D 6th
HOW TO SOLVE THIS ?

First of all find the ratio d/λ using using "dsin(theta)=nλ putting n=3 and theta = 45

then use value of this ratio by again using the same formula but putting sin(theta) = 1 because this is its max value. This way you'll get value of new n in decimal form. The answer will be the whole number just below that decimal value.

EDIT: I guess you must wait at least for an hour before copying, pasting and posting the question again. =/

 

[aliya_zad]

A narrow beam of monochromatic light is incident normally on a diffraction grating. Third-order
diffracted beams are formed at angles of 45
o to the original direction.
What is the highest order of diffracted beam produced by this grating?
A 3rd B 4th C 5th D 6th
HOW TO SOLVE THIS ?

First of all find the ratio d/λ using using "dsin(theta)=nλ putting n=3 and theta = 45

then use value of this ratio by again using the same formula but putting sin(theta) = 1 because this is its max value. This way you'll get value of new n in decimal form. The answer will bt the whole number just below that decimal value.

EDIT: I guess you must wait at least for an hour before copying, pasting and posting the question again. =/

The ans is B rite?

 

[Hateexams93]

yes its B

 

[Zishi]

A narrow beam of monochromatic light is incident normally on a diffraction grating. Third-order
diffracted beams are formed at angles of 45
o to the original direction.
What is the highest order of diffracted beam produced by this grating?
A 3rd B 4th C 5th D 6th
HOW TO SOLVE THIS ?

First of all find the ratio d/λ using using "dsin(theta)=nλ putting n=3 and theta = 45

then use value of this ratio by again using the same formula but putting sin(theta) = 1 because this is its max value. This way you'll get value of new n in decimal form. The answer will bt the whole number just below that decimal value.

EDIT: I guess you must wait at least for an hour before copying, pasting and posting the question again. =/

The ans is B rite?

Yep.

 

[Hateexams93]

hm..voltmeter reading ..isn't it supposed to be 3 ?

 

[Zishi]

hm..voltmeter reading ..isn't it supposed to be 3 ?

A. The circuit hasn't changed.