1
NEET 2018
MCQ (Single Correct Answer)
+4
-1
Change Language
Three objects, A : (a solid sphere), B : (a thin circular disk) and C : (a circular ring), each have the same mass M and radius R. They all spin with the same angular speed $$\omega $$ about their own symmetry axes. The amounts of work (W) required to bring them to rest, would satisfy the relation
A
WC > WB > WA
B
WA > WB > WC
C
WB > WA > WC
D
WA > WC > WB
2
NEET 2018
MCQ (Single Correct Answer)
+4
-1
Change Language
Two wires are made of the same material and have the same volume. The first wire has cross-sectional area A and the second wire has cross-sectional area 3A. If the length of the first wire is increased by $$\Delta $$l on applying a force F, how much force is needed to stretch the second wire by the same amount?
A
6F
B
F
C
9F
D
4F
3
NEET 2018
MCQ (Single Correct Answer)
+4
-1
Change Language
A tuning fork is used to produce resonance in a glass tube. The length of the air column in this tube can be adjusted by a variable piston. At room temperature of 27°C two successive resonances are produced at 20 cm and 73 cm of column length. If the frequency of the tuning fork is 320 Hz, the velocity of sound in air at 27°C is
A
330 m s–1
B
339 m s–1
C
350 m s–1
D
300 m s–1
4
NEET 2018
MCQ (Single Correct Answer)
+4
-1
Change Language
An electron falls from rest through a vertical distance h in a uniform and vertically upward directed electric field E. The direction of electric field is now reversed, keeping its magnitude the same. A proton is allowed to fall from rest in it through the same vertical distance h. The time of fall of the electron, in comparison to the time of fall of the proton is
A
smaller
B
5 times greater
C
10 times greater
D
equal