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A long solenoid of diameter 0.1m has 2×10⁴ turns per meter. At the centre of the solenoid, a coil of 100 turns and radius 0.01m is placed with its axis coinciding with the solenoid axis. The current in the solenoid reduces at a constant rate to 0A from 4A in 0.05s . If the resistance of the coil is 10π²Ω , the total charge flowing through the coil during this time is

The inner coil will generate emf due to the flowing current in the long solenoid. Current will pass through the... View Article

A parachutist after bailing out falls 50m without friction. When the parachute opens, it decelerates at 2ms⁻². He reaches the ground with speed 3ms⁻². At what height did he bail out?

The fundamental concepts of motion of any object are described by the basic equations of motion. These equations control an... View Article

The amplitude of a particle executing SHM about O is 10cm. Then(A) When the K.E. is 0.64 of its max. K.E. its displacement is 6cm from O. (B) When the displacement is 5cm from O its K.E.is 0.75 of its max. P.E. (C) Its total energy at any point is equal to its maximum K.E. (D) Its velocity is half the maximum velocity when its displacement is half the maximum displacement.

We know that in SHM, total mechanical energy is conserved: ME = KE + PE ME = KEmax ME =... View Article

An engine is moving on a circular path of radius 100 metre with a speed of 20 metre per second. The frequency observed by an observer standing stationary at the centre of circular path when the engine blows a whistle of frequency 500 Hz is

answer (c) Explanation There is no doppler effect, since the relative velocity of the engine is perpendicular to the observer.... View Article

In the circuit diagram, find the current through the Zener diode given below

Since the resistance R2 and the Zener diodes are linked in parallel, the voltage across them is equal, resulting in a... View Article

A constant force acts on an object of mass 5 Kg for a duration of 2 seconds. It increases the objects v=u+atvelocity from 3m/s to 7m/s . Find the magnitude of the applied force. Now if the tax were applied for a duration of 5seconds, what would be the final velocity of the object ?<

The initial and final velocity of the items are given, however we must assume that initial and final velocity. We... View Article

A bead of mass m is attached to one end of the spring of natural length R and spring constant K=(√3+1)mg/R. The other end of the spring is fixed at point A on a smooth vertical ring of radius R as shown in fig. The normal reaction at B just after it is released to move is

In ΔAOM and ΔBOM, AM=BM=Rcos30⇒AM=BM = √3/2R The spring is stretched and hence its length is extended. Given, R is... View Article

The number of stereoisomers obtained by bromination of trans-2-butene is: a) 1 b) 2 c) 3 d) 4

Answer: (a) 1 Explanation Addition of halogens to alkenes is predominantly anti-addition. Anti-addition of Br2 on trans alkene produces meso... View Article

which of the following alkene is most stable? A) CH2=CH−CH2−CH3 B) CH2=C(CH3)−CH=CH2 C) CH2=CH−CH=CH2 D) CH3−CH=CH−CH3

Answer: (b) Explanation Alkene stability is determined by a number of variables. Let’s talk about those elements and then try... View Article

The most reactive towards electrophilic reagent is :

a) b) c) d) Answer: (d) o-hydroxy toluene Explanation Electron-releasing groups raise the total electron density and thus the benzene... View Article

A rectangular loop of sides 10cm and 5cm carrying a current I of 12A is placed in different orientations as shown in the figure below: If there is a uniform magnetic field of 0.3T in the positive z-direction, in which orientations the loop would be in (A) Stable equilibrium and (B) Unstable equilibrium?

Only torque acts on a current carrying loop because the magnetic field B is uniform. The vector product of the... View Article

A series combination of n1 capacitors, each of value C1, is charged by a source of potential difference 4V. When another parallel combination of n2 capacitors, each of value C2, is charged by a source of potential difference V, it has the same (total) energy stored in it, as the first combination has. The value C2, in terms of C1, is?

E is the energy stored by a capacitor of capacitance C at the potential difference of V is E = 1/2CV2... View Article

The fundamental frequency in an open organ pipe is equal to the third harmonic of a closed organ pipe. If the length of the closed organ pipe is 20cm, the length of the open organ pipe is

The first is when the pipe is open at both ends, while the second is when the pipe is closed... View Article

A bulb is placed at a depth of 2√7m in water and a floating opaque disc is placed over the bulb so that the bulb is not visible from the surface. The radius of the disc should be at least (μ water =4/3) (Note, centre of disc is on the vertical line above the bulb) :

From the periphery, light should be internally reflected. For total internal reflection sinθ = μ1 R/√R2+(2√7)2 = 1//4/3 = 3/4 ⟹ R2/ R2 + 28... View Article

A rectangular loop with a sliding connector of length=1.0m is situated in a uniform magnetic field field=2t perpendicular to the plane of loop. Resistance of the connector is r=2Ω . Two resistance is 6Ω and 3Ω are connected as shown in the figure. The external force required to keep the connector moving with a constant velocity v=2ms⁻¹

In this question it is given that, the resistance of the connector 2Ω magnetic field – 2t two resistance –... View Article

A solenoid has a core of a material with relative permeability 400. The windings of the solenoid are insulated from the core and carry a current of 2A. If the number of turns is 1000 per meter, calculate (a) H, (b) B and (c) the magnetic current Im.

We have to calculate thethe magnetic field: B = μoμrnI ; Put the given values in the above equation and... View Article

For an ideal solution, the correct option is: (A) ΔmixS=0 at constant T and P (B) ΔmixV≠0 at constant T and P (C) ΔmixH=0 at constant T and P (D) ΔmixG=0 at constant T and P

An ideal solution obeys Raoult’s Law. According to the Raoult’s Law “For a solution of volatile liquids, the partial vapour... View Article

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