A metal foil of neglible thickness is introduced between two parallel plates of a capacitor at the centre. The new capacitance of the capacitor would be :

In visible light, orange differs from violet as they have

To get eight images of a single object one should have two plane mirror at an angle of :

A photo cathode is illuminated by a very small bright source placed 1 m away. When the same source of light is placed 0.5 m away, the number of electrons emitted by the photo cathode would become

Match List-I with List-II

List-I (Electric Field)	List-II (Expression)
(A) Field due to an infinitely long straight uniformly charged wire	(I) \(\sigma\left(2 \varepsilon_0\right)^{-1}\)
(B) Field due to a uniformly charged thin spherical shell (inside the shell)	(II)\(q\left(4 \pi \varepsilon_0 r^2\right)^{-1}\)
(C) Field due to a uniformly charged infinite plane sheet	(III) \(\lambda\left(2 \pi \varepsilon_0 r\right)^{-1}\)
(D) Field due to a uniformly charged thin spherical shell (outside the shell)	(IV) zero

Choose the correct answer from the options given below:

In an intrinsic semiconductor at room temperature ;

When a deuteron is bombarded on \(^{16}_{8}\text{O}\) nucleus, an α-particle is emitted. Other product nucleus is:

A coil of 400 turns of effective area \(0.05 \text{ m}^2\) is kept perpendicular to a magnetic field of \(5 \times 10^{-3} \text{ T}\). When the plane of coil is rotated by \(90^\circ\) around any of its co-planar axis in 0.2 s in magnetic field, the emf induced in the coil is

Read the following paragraph carefully and answer the given questions.
Certain types of leukocytes (WBC) of our body like polymorpho-nuclear leukocytes (PMNL-neutrophils) and monocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytose and destroy microbes. For determining the cause of allergy, the patient is exposed to or injected with very small doses of possible allergens, and the reactions studied. The use of drugs like anti-histamine, adrenalin and steroids quickly reduce the symptoms of allergy. Heroin, commonly called smack is chemically diacetylmorphine which is a white, odourless, bitter crystalline compound. This is obtained by acetylation of morphine. Techniques like radiography (use of X-rays), CT (computed tomography) and MRI (magnetic resonance imaging) are very useful to detect cancers of the internal organs. Different species of Plasmodium (P. vivax, P. malaria and P. falciparum) are responsible for different types of malaria. Of these, malignant malaria caused by Plasmodium falciparum is the most serious one and can even be fatal.
Malignant malaria is caused by -

When a ray of light enters from denser medium to rarer medium, its velocity is doubled. The critical angle for total internal reflection will be :

The focal length of a thin lens in vacuum is f. If the material of the lens has refractive index \( \frac{3}{2} \), its focal length when immersed in water of refractive index \( \frac{4}{3} \) would be :

The supply function of a commodity is \(P=x^3+2 x+18\). When 4 units of the commodity are sold, then producer surplus is:

If the slope of the tangent to the curve \(y=y(x)\) at any point \((x, y)\) is \(\frac{2 x}{y^2}\) and the curve passes through the point \(\left(\frac{1}{\sqrt{3}}, 1\right)\), then the equation of the curve is :