Two identical thin metal strips, one of aluminum and the other of iron are riveted together to form a bimetallic strip. The temperature is raised by 50°C. If the central planes of the two strips are separated by 2 mm and the coefficients of thermal expansion for aluminum and iron are respectively 30 x 10^-6 / °C and 10 x 10^-6 / °C, the average radius of curvature of the bimetallic strip is about 

(a) 50 cm (b) 100 cm (c) 150 cm (d) 200 cm 

A convex lens and concave lens are kept in contact and the combination is used for the formation of image of a body by keeping it at different places on the principal axis. The image formed by this combination of lenses can be : 

(A) Magnified, inverted and real

(B)  Diminished, inverted and real

(C) Diminished, erect and virtual

(D) Magnified, erect and virtual 

The equation correctly represented by the following graph is (a and b are constants)

(A)   x + y = b

(B)   ax² + by² = 0 

(C)   x + y = ab 

(D)  y = ax^b

Let a body be placed at a point on the earth’s surface at a latitude λ where the radius of the earth is R. Then, the body experiences an effective acceleration

(a)  g – Rω² cos λ

(b)  g + Rω² sin λ

(c)  g – Rω² cos² λ

(d)  g – Rω²/ cos²λ

An isolated metallic object is charged in vacuum to a potential V₀ using a suitable source, its electrostatic energy being W₀. It is then disconnected from the source and immersed in a large volume of dielectric with dielectric constant K. The electrostatic energy of the sphere in the dielectric is :

(A)  K²W₀

(B)   K W₀

(C)   W_0/K²

(D)  W₀/K

An object is placed 30 cm away from a symmetric convex lens and an image two thirds of the size of the object is produced. The object is moved by a distance of 20 cm so as to get a magnified image. Now we get 

(a)  a real image of magnification 

(b)  a virtual image of magnification 5 

(c)  a real image at a distance of 40 cm 

(d)  a virtual image at a distance of 60 cm

Which of the following will give a straight line graph? 

(a) log A against t (b) log A against1/t (c) A against t² (d) A² against t

Consider two point masses m₁ and m₂ connected by alight rigid rod of length r₀. The moment of inertia of the system about an axis passing through their centre of mass and perpendicular to the rigid rod is given by

A particle moves in a plane with a constant speed along a path y = 2x² + 3x – 4. When the particle is at (0, – 4) the direction along which it is moving is inclined to the X axis at an angle 

(a) 63⁰ (b) 72⁰ (c) 27⁰ (d) 0⁰

Refer to the circuit given below. Output voltage V₀ is measured between points a and b. Then,

(a)  the peak value of V₀ is 2.5 V above the minimum if the diode is assumed to be ideal 

(b)  the positive half cycle of the input is clipped 

(c)  the circuit acts as a rectifier 

(d)  the peak value V₀ is about 3.2 V above the minimum if D is silicon diode (non-ideal)