0
Q:

# A boy is swinging a ball attached to a string in a horizotal circle. If the string snaps

 A) the ball will travel towards the center of the circle and fall down B) it will continue to travel along a tangent to the circle at the point the ball was at the time of snapping and finally fall down C) it will fall down at the same place where the string breaks D) None of these

Answer:   B) it will continue to travel along a tangent to the circle at the point the ball was at the time of snapping and finally fall down

Explanation:

The centripetal force having been removed the body cannot  execute the curved path

Subject: Physics
Q:

A disk and a sphere of same radius but different masses roll on two inclined planes of the same altitude and length. Which one of the two objects gets to the bottom of the plane first ?

 A) Depends on their masses B) Sphere C) Disk D) Both reach at the same time

Explanation:

Time does not depend on mass, else

$\inline \fn_jvn T \prec \sqrt{\left ( 1 +\frac{k^{2}}{R^{2}} \right )}$

$\inline \fn_jvn \frac{k^{2}}{R^{2}}$  => is least for 'sphere' and

hence least time is taken by sphere.

Filed Under: Physics
Exam Prep: AIEEE

1 111
Q:

A potentiometer wire is 100 cm long and a constant potential difference is maintained across it. Two cells are connected in series first to support one another and then in opposite direction. The balance points are obtained at 50 cm and 10 cm from the positive end of the wire in the two cases. The ratio of the emf's is :

 A) 3:4 B) 5:4 C) 5:1 D) 3:2

Explanation:

In series : E1 + E2 = K(50)

In parallel : E1 - E2 = K(10)

E1 + E2 / E1 - E2 = 5/1

=> E1/E2 = 3/2

The emf's are in the ratio of 3:2.

Filed Under: Physics
Exam Prep: AIEEE

2 97
Q:

What is the maximum velocity with which a body of mass 'm' must enter a vertical loop of radius 'R'so that it can complete the loop ?

A) $\inline \fn_jvn \sqrt{2gR}$   B) gR   C)  $\inline \fn_jvn \sqrt{5gR}$  D)  $\inline \fn_jvn \sqrt{2g/R}$

 A) A B) B C) C D) D

Explanation:

To complete the vertical loop, the minimum speed required at the lowest point  = $\inline \fn_jvn \sqrt{5gR}$ .

Filed Under: Physics
Exam Prep: AIEEE

1 21
Q:

Which of the following group of elements are diamagnetic ?

 A) Argon, copper, silver B) Hydrogen, argon, copper C) Oxygen, copper, silver D) Hydrogen, oxygen, Argon

Explanation:

Filed Under: Physics
Exam Prep: AIEEE

1 30
Q:

At the Curie temperature, the ferromagnetic materials get converted into

 A) Diamagnetic materials B) Non-magnetic materials C) Paramagnetic materials D) None of the others