Recent questions tagged class12

A thin prism of angle $8^{\circ}$ produces a deviation of $4 ^{\circ} [\delta =4^{\circ}]$ What is the refractive index of the material of the prism.

asked Jan 17, 2014 by meena.p

1 answer

The wave length of light in 1st liquid is $2500 \;\mathring{A}$, and that in 2nd liquid is $5000\; \mathring{A}$, What is the critical angle of 1st liquid with respect to 2nd liquid.

asked Jan 17, 2014 by meena.p

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In a binomial distribution the mean is 15 and variance is 10, then parameter $n$ is

asked Jan 16, 2014 by thanvigandhi_1

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Probability of getting positive integral roots of the equation $ x^2-n=0$ for the integer $ n \: \: \: 1 \leq n \leq 40$ is

asked Jan 16, 2014 by thanvigandhi_1

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Twelve tickets are numbered from 1 to 12. One tickets is drawn at random, then the probability of the number to be divisible by 2 or 3 is

asked Jan 16, 2014 by thanvigandhi_1

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If X is a Poisson variate such that $ P(X=1)=P(x=2)$ the $P(x=4)$ is equal to

asked Jan 16, 2014 by thanvigandhi_1

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A fair die is tossed eight times. The probability that a third six is observed on the eight throw is

asked Jan 16, 2014 by thanvigandhi_1

1 answer

The mean and standard deviation of a binomial variate X are 4 and $ \sqrt 3$ respectively. The $P( X \geq 1 )$ is equal to

asked Jan 16, 2014 by thanvigandhi_1

1 answer

A swimmer is swimming at a depth of 12 m below the surface. A bird flying in the sky appears 36 m directly above his eyes. At what height is the bird is actually flying from the surface of water

asked Jan 16, 2014 by meena.p

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If X is a binomial variate with the range { 0,1,2,3,4,5,6 } and P(X = 2)=4P (x=4) then the parameter P of X is

asked Jan 16, 2014 by thanvigandhi_1

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Refractive index for a piece of transparent material is greatest for

asked Jan 16, 2014 by meena.p

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An object is placed in front of a concave mirror of focal length f. A virtual image of magnification 2 is formed.How for must the object be moved from original position so that a real image of same size is formed.

asked Jan 16, 2014 by meena.p

1 answer

If $P(A)=P(B)=x\: and \: P(A \cap B ) = P(A' \cap B')=\large\frac{1}{3}$ then x is equal to

asked Jan 16, 2014 by thanvigandhi_1

1 answer

If $P(A)=\large\frac{1}{12}\: P(B)=\large\frac{5}{12}\: and \: P(B/A) = \large\frac{1}{15}$ then $P(A \cup B )$ is equal to

asked Jan 16, 2014 by thanvigandhi_1

1 answer

A random variable X follows binomial distribution with mean $ \alpha$ and variance $ \beta$ Then

asked Jan 16, 2014 by thanvigandhi_1

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The chances to fail in Physics are 20% and the chances to fail in Mathematics are 10%. What are the chances to fail in at least one subject ?

asked Jan 16, 2014 by thanvigandhi_1

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A bag contains 3 black, 3 white and 2 red balls. One by one three balls are drawn without replacement. The probability that the third ball is red is equal to

asked Jan 16, 2014 by thanvigandhi_1

1 answer

A person has two children. If one of them is boy, then the probability that other is also a boy is

asked Jan 16, 2014 by thanvigandhi_1

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A right angled prism ABC is dipped in water . such that the surface AB is in air as shown. A ray of light is normally. What must be the possible value of $\theta$ so that the say gets totally reflected at AC to reach surface BC.

asked Jan 16, 2014 by meena.p

1 answer

A ray of light is incident on side of a right angled prism normally. It then falls on the hypotenuse of the prism and gets reflected back as shown. If $\theta=45^{\circ}$ then the refractive index of the material of prism is

asked Jan 16, 2014 by meena.p

1 answer

A ray of light travelling in glass enters glass water interface at an angle $\theta$. It finally emerges into air parallel to the surface of water. $ \mu_w=\large\frac{4}{3}$. What is the refractive index of glass.

asked Jan 16, 2014 by meena.p

1 answer

A combination of lens is formed by keeping two identical equiconvex lens of focal length f kept in contact and the space between them filled with liquid of refractive index $\mu_2 =\large\frac{4}{3}$. Focal length of the combination is

asked Jan 16, 2014 by meena.p

1 answer

A ray of light is incident on glass sphere of refractive index $\large\frac{3}{2}$. The ray incident at two surfaces after travelling through the sphere emerges tangential to the surface of the sphere. What must be the incident angle.

asked Jan 16, 2014 by meena.p

1 answer

A small point object is inside a glass surface as shown. Refraction takes place at concave spherical boundry separating glass air medium. For the image to be real the object distance u is (R-Radius of curvature of the surface , $\mu of glass =\large\frac{3}{2}$ )

asked Jan 16, 2014 by meena.p

1 answer

Position of object (u) reflected from concave varies from $0$ to $\infty$ which of the graph represents the variation of object distance (v) with respect to (u)

asked Jan 16, 2014 by meena.p

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A glass slab of refractive index $1.5$ and thickness $3\;cm$ is placed on a black dot on a piece of paper. A person looks at the mark from a height of $8\; cm $ above it. The dot will appear at a distance.

asked Jan 16, 2014 by meena.p

1 answer

A ray of light is incident from air on a surface of medium at an angle of $60^{\circ}$. The angle of refraction in the medium is $ 30^{\circ}$ what will be the velocity of light in the medium.

asked Jan 16, 2014 by meena.p

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A ray of light is incident on a rectangular glass block at $45^{\circ}$ on glass- air interface. The refractive index of glass is $\sqrt 2$. Then

asked Jan 16, 2014 by meena.p

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light travels through a glass of refractive index $\mu =1.5 $ of thickness $4 mm$. What is the time taken for the light to cross it

asked Jan 16, 2014 by meena.p

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A light wave has wavelength $6000 \mathring{A}$ in vacuum. The wavelength of this light when it passes through a certain glass of refraction index $(\mu =1.5 ) $ is

asked Jan 16, 2014 by meena.p

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Wavelength of a colour of light for air is $6000\;\mathring{A}$ and in water the wavelength is $4500\;\mathring{A}$. What is the speed of light in water.

asked Jan 16, 2014 by meena.p

1 answer

Image formed by a concave mirror of is three times of the object Focal length of the mirror is 6 cm. Then the object distance is

asked Jan 16, 2014 by meena.p

1 answer