1
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
2
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
3
NEET 2018
MCQ (Single Correct Answer)
+4
-1
Change Language
The moment of the force, $$\overrightarrow F = 4\widehat i + 5\widehat j - 6\widehat k$$ at
(2, 0, –3), about the point (2, –2, –2), is given by
A
$$ - 8\widehat i - 4\widehat j - 7\widehat k$$
B
$$ - 4\widehat i - \widehat j - 8\widehat k$$
C
$$ - 7\widehat i - 8\widehat j - 4\widehat k$$
D
$$ - 7\widehat i - 4\widehat j - 8\widehat k$$
4
NEET 2018
MCQ (Single Correct Answer)
+4
-1
Change Language
A small sphere of radius ‘r’ falls from rest in a viscous liquid. As a result, heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity, is proportional to
A
r3
B
r2
C
r5
D
r4