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The height of a cone is 15 cm and its volume is 1570 cm3. Find the radius of the base. (Use π = 3.14)

Answer: A cone is a shape formed by using a set of line segments or the lines which connects a common point, called the apex or vertex, to all... View Article

If force F, work W and velocity v are taken as fundamental quantities. What is the dimensional formula of time?

Answer: Velocity is defined as the rate of change of the object’s position with respect to a frame of reference and time. Work is... View Article

If force F, time t and velocity V are taken as fundamental quantities and K is the dimensionless constant of proportionality. What is the dimensional formula for mass?

Answer: Velocity is defined as the rate of change of the object’s position with respect to a frame of reference and time. Work is... View Article

The difference between a 2-digit number and the number obtained by interchanging the digits is 36. What is the difference between the sum and the difference of the digits of the number if the ratio between the digits of the number is 1:2 ? (1) 4 (2) 8 (3) 16 (4) None of these

The difference between a 2-digit number and the number obtained by interchanging the digits is 36. What is the difference between the sum and the... View Article

The position of a body moving along x-axis at time t is given by x = (t²– 4t + 6)m. The distance travelled by body in time interval t = 0 to t = 3s is (1) 5m (2) 7m (3) 4m (4) 3m

Answer: (1) 5m x = t2 - 4t + 6The change in velocity is expressed as .The velocity is changing At t = 0, x1= 6 At t = 2, x2 = 2 Magnitude... View Article

A jet airplane travelling at the speed of 500 kmh^-1 ejects its products of combustion at the speed of 1500 kmh^-1 relative to the jet plane. What is the speed of the latter with respect to an observer on ground? (1) 500 km h^-1 (2) -1000 km h−1 (3) 1500 kmh^-1 (4) 2000 kmh^-1

Answer: - 1000kmh-1 Relative velocity is defined as the velocity of an object B in the rest frame of another object A. The difference between... View Article

A particle of mass m is moving in a circular path of constant radius r such that centripetal acceleration is varying with time t as k²rt², where k is a constant. The power delivered to the particle by the force acting on it is (1) m²k²r²t² (2) mk²r²t (3) mk²rt² (4) mkr²t

Answer: Centripetal acceleration is defined as the property of the motion of an object, traversing a circular path. Any object that is moving in... View Article

The distance x covered by a particle in one-dimensional motion varies with time t as x² = at² + 2bt + c. The acceleration of the particle varies as (1) x−3 (2) x^3/2 (3) x² (4) x^-2/3

Answer: x-3 Let v be velocity,α be the acceleration then, x2 = at2 + 2bt + c 2xv = 2at + 2b xv = at + b_____________(1) v = (at + b)/x... View Article

A pump motor is used to deliver water at a certain rate from a given pipe. To obtain thrice as much water from the same pipe at the same time, the power of the motor has to be increased to (1) 2 times (2) 9 times (3) 27 times (4) 81 times

Answer:(3) 27 times Power is defined as the rate of doing work, it is the work done in unit time. The SI unit of power is Watt (W) which is... View Article

A charge particle (charge q) is moving in a circle of radius R with uniform speed. v The associated magnetic moment m is given by_______

Answer: A charge particle (charge q) is moving in a circle of radius R with uniform speed. v The associated magnetic moment m is given by qvR/2.... View Article

For a plane convex lens (μ=1.5) having radius of curvature 10cm. It is silvered on its plane surface. Find focal length after silvering (1) 10cm (2) 20cm (3) 15cm (4) 25cm

Answer: (1) 10cm An optical lens is generally made up of two spherical surfaces. If those surfaces are bent outwards, the lens is called a... View Article

Calculate the ratio of 4th Bohr’s to 2nd Bohr’s orbit of He⁺ ion.

Answer: The Bohr model suggests that the electrons in atoms are in various energy orbits around the nucleus. In defining these orbits of varying... View Article

A ball initially at rest and it is dropped from building of height 10 m to ground. If the coefficient of restitution is e = 0.7. After collision, the ball rebounds back up to height h, find the value of h. (g = 9.8 m/s²)

Answer: A ball initially at rest and it is dropped from building of height 10 m to ground. If the coefficient of restitution is e = 0.7. After... View Article

A body starts from rest with uniform acceleration. The velocity of the body after t seconds is v. The displacement of the body in last three seconds is (1) 3v/2[(t – 3)] (2) 3v/2[(t + 3)] (3) 3v[1 – 3/2t] (4) 3v[1 + 3/2t]

Answer: (3) 3v[1 - 3/2t] Let a be the uniform acceleration of the body . Then v = at a = v/t____________(1) Displacement is calculated as the... View Article

A ring of radius 1 m is lying on the surface of liquid. It is lifted from the liquid surface by a force of 4 newtons in such a way that the liquid film in it remains intact. What is the surface tension of liquid?

Answer: Surface tension is the tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the... View Article

The potential difference V and the current I flowing through an instrument in an AC circuit are given by V = 5cosωt volt, I = 2sinωt Amp . The power dissipated in the circuit is (1) 5 watt (2) 10 watt (3) 2.5 watt (4) 0

Answer: (4) 0 In an AC circuit, the power dissipated in the circuit is given as follows P = Vrms Irms cosϕ The ϕ is the phase difference... View Article

A person is unable to see objects nearer than 50cm. He wants to read a book placed at a distance of 25cm. Find the nature of focal length and power of the lens, he needs for his spectacles.

A person is unable to see objects nearer than 50cm. He wants to read a book placed at a distance of 25cm. Find the nature of focal length and... View Article

Three bulbs A, B and C are connected as shown in the figure. The bulbs B and C are identical. If bulb C is fused, then (1) Brightness of both bulbs A and B will increase (2) Brightness of both bulbs A and B will decrease (3) Brightness of bulb A decrease and that of bulb B increases (4) None of the bulbs will glow

Answer:(3) Brightness of bulb A decrease and that of bulb B increases Bulbs B and C are connected in parallel and bulb A is connected in series... View Article

About which of the following axes moment of inertia of a circular disc is minimum? (1) Axis passing through its centre and perpendicular to its plane. (2) Axis along the diameter. (3) Axis along the tangent and in its own plane (4) Axis along the tangent and perpendicular to its plane.

Answer: (2) Axis along the diameter Moment of inertia is defined as the quantity expressed by the body resisting angular acceleration which is... View Article

An object at a distance of 30 cm from a concave mirror gets its image at the same point. The focal length of the mirror is (1) -30cm (2) +30cm (3) -15cm (4) +15cm

Answer: (3) -15cm If a hollow sphere is cut into parts and the outer surface of the cut part is painted, then it becomes a mirror with its inner... View Article

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