A dentist has a small mirror of focal length \(1 . 6 ~ c m\). He observes the cavity in the tooth of a patient by holding the mirror at a distance of 8 mm . from the cavity. The magnification is:

Which of the following causes electric conduction in a semiconductor?

Which of the following statements are correct?
(A) Total internal reflection occurs when a ray of light travels from a rarer transparent medium to a denser medium.
(B) In total internal reflection, the incident ray of light remains in the same medium after reflection.
(C) In total internal reflection, the angle of incidence inside the denser transparent medium is equal to the angle of reflection in the same medium.
(D) In total internal reflection inside a denser medium there is no angle of refraction
Choose the correct answer from the options given below:

The potential of a charged spherical conductor of radius r is 20V. The potential at a point r/4 from its center is:

Which of the following is NOT correct in the case of the output obtained from a full wave rectifier?

Two wires of equal lengths carrying equal currents bent in the form of two loops, one in square shape and the other in circular shape having one turn only are suspended in same, uniform magnetic field perpendicular to the plane of loops. Choose the correct option

A battery of 200 V charges a capacitor to \( 10 \times 10^{-6} \, C \). Now the battery is disconnected, and the plate separation is doubled. The potential of the capacitor will be

Read the passage carefully and answer the Questions
The term vitamin was coined from the word vital +amine since the earlier identified compounds had amino groups. Later work showed that most of them didn't contain amino groups. They are very essential for the body. They has to be taken various diet or in the form of medicines also.
Vitamins are classified into two groups depending upon their solubility in water or fat.
Fat soluble vitamins are soluble in fat and oils but insoluble in water. They are stored in liver and adipose (fat storing) tissues Water-soluble vitamins are soluble in water. These must be supplied regularly in diet because they are readily excreted in urine and cannot be stored in our body.
Which vitamin is known as Riboflavin?

The corner points of a bounded feasible region are \(( 0 , 5 ),( 6 , 1 ),( 1 7 , 2 )\) and \(( 4 , 2 9 )\).
If the maximum value of the objective function \(z=p x+q y\), where \(p>0\) and \(q>0\), occurs at two points \((17,2)\) and \((4,29)\), then the relation between \(p\) and \(q\) is :

If \(z=3 x+4 y\) be the objective function of a linear programming problem (LPP) and (3,1), (2,4), (0,4), (5,0) be corner points of the bounded feasible region. Then the maximum value of objective function is

In the following sequence of reactions :
CH3–CH(NH2) - CH3 $\xrightarrow{HNO_2}$[A] $\xrightarrow{Oxidation}$[B] $\xrightarrow{H^{+}/H_{2}O}$ CH3MgBr
[C] The compound [C] is :

For a chemical reaction.
(A) The order of a reaction is the sum of powers of the concentration of the reactants.
(B) The order of a reaction may be zero, an integer or a fractional value.
(C) Molecularity of an elementary reaction is equal to the number of reacting species.
(D) The molecularity of a reaction may be zero or a fractional value.
Choose the correct answer from the options given below:

Read the following passage carefully and answer the given questions.
Insulin consists of two short polypeptide chains- chain A and chain B, that are linked together by disulphide bridges. Some strains of Bacillus thuringiensis produce proteins that kill certain insects such as lepidopterans, coleopterans and dipterans. Bt toxin protein is converted into an active form of toxin due to the alkaline pH of the gut which solubilise the crystals. Transgenic animals that produce useful biological products can be created by the introduction of the portion of DNA (or genes) which codes for a particular product such as human protein (alpha-1-antitrypsin) used to treat emphysema. Plants, bacteria, fungi and animals whose genes have been altered by manipulation are called Genetically Modified Organisms (GMO). GM plants have been useful in many ways. Genetic modification has: (i) made crops more tolerant to abiotic stresses. (ii) reduced reliance on chemical pesticides (pest-resistant crops). (iii) helped to reduce post harvest losses. (iv) increased efficiency of mineral usage by plants (this prevents early exhaustion of fertility of soil). (v) enhanced nutritional value of food.
Transgenic animals that produce useful biological products such as human protein (alpha-1-antitrypsin) used to treat the disorder: