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A ball falls from height h. After 1 s, another ball falls freely from a point 25m below the point from where the first ball falls. Both of them reach the ground at the same time. The value of h is

a) 11.2 m b) 21.2 m c) 31.2 m d) 41.2 m Answer: c) 31.2 m Solution: For the first ball, h = (1/2)gt2 -------(1) For the second ball, (h -... View Article

A luminous point object is moving along the principal axis of a concave mirror of focal length 12 cm towards it. When its distance from mirror is 20 cm its velocity is 4 cm/s. The velocity of the image in cm/s at that instant is:

a) 6, towards the mirror b) 6, away from the mirror c) 9, away from the mirror d) 9, towards the mirror Answer: c) 9, away from the... View Article

The dimensional formula of L/R is same as that of (where L is inductance and R is resistance)

a) (frequency)2 b) time period c) frequency d) (time period)2 Answer: b) time period Solution: Dimensional formula of L is... View Article

An optical bench has 1.5 m long scale having four equal divisions in each cm. While measuring the focal length of a convex lens, the lens is kept at 75 cm mark of the scale and the object pin is kept at 45 cm mark. The image of the object pin on the other side of the lens overlaps with image pin that is kept at 135 cm mark. In this experiment, the percentage error in the measurement of the focal length of the lens is ____ .

Answer: 1.39% Solution: u = distance of the object from the lens u = - (75 -45) u = -30 cm v = distance of the image from the lens v = 60... View Article

A body with mass 5 kg is acted upon by a force [latex]F = (-3hat{i}+4hat{j})[/latex] N. If its initial velocity at t=0 is [latex]v = (6hat{i}-12hat{j})m/s[/latex], the time at which it will just have a velocity along the y-axis is

a) never b) 10 s c) 2 s d) 15 s Answer: b) 10 s Solution: Force along x-axis, Fx = -3 ax = Fx/5 = -3/5 ux = 6 v = u + at... View Article

In the given circuit, the current through Zener diode is

a) 2.5 mA b) 3.3 mA c) 5.5 mA d) 6.7 mA Answer: b) 3.3 mA Solution: Voltage across R1 is given by VR1=V−Vz=15−10=5V. Resistance R1=500Ω... View Article

A charge q is placed at the centre of cubical box of side a with the top open. The flux of the electric field through one of the surface of the cubical box is

Answer: q/6ε0 Solution: Net flux = q/ε0 Total number of face = 6 Flux through one of the face... View Article

How to convert improper fraction to mixed fraction?

As we know, for an improper fraction, the numerator is greater than the denominator.To convert the improper fraction to mixed fraction, follow... View Article

Expand: (x-1)^3

Given expression: (x - 1)3Using the algebraic identity: (a - b)3 = a3 - b3 - 3ab(a - b)(x - 1)3 = x3 - 13 - 3(x)(1)(x - 1)= x3 - 1 - 3x(x - 1)=... View Article

How to calculate the percentage of marks?

Percentage of marks can be calculated using the below formula: Percentage of marks = (Obtained marks/Maximum marks) × 100 Two simple steps... View Article

Is 343 a prime number?

No, 343 is not a prime number. Reason: The number 343 has more than two factors, i.e. it has factors other than 1 and the number itself. Factors... View Article

How to calculate the percentage using a formula?

Percentage formula = (value/total value) × 100We can find the p% of a number M as:p% of M = (p/100) × MSimilarly, How much percentage... View Article

How to find simple interest?

Simple interest can be calculated using the formula, SI =PTR/100 Here, SI = Simple interest P = Principal amount T = Time (in years) R =... View Article

What is the derivative of cos^2x?

Let y = cos2xDifferentiating on both sides, w.r.t x, we get;dy/dx = d/dx (cos2x)= (d/dx) (cos x)2= 2 cos x (d/dx) cos x= 2 cos x (-sin x)= -2 sin... View Article

Find the prime factorization of 5929.

Prime factorization of 5929 = 7 x 7 x 11 x 11... View Article

How do students learn to visualize function transformations?

Visualization refers to the graphical representation of any function. It is helpful in understanding the nature of the given function and... View Article

Which is more dangerous type 1 or type 2 error in statistics?

When we move forward with any hypothesis to test it with statistical analysis, we begin with the assumption that the null hypothesis is correct.... View Article

At what distance from a convex mirror of focal length 2.5 m should a small object be kept so that its image has height of half of original height of object?

At what distance from a convex mirror of focal length 2.5 m should a small object be kept so that its image has height of half of original height... View Article

Give 5 examples of data that you can collect from day to day life and represent them in tabular form.

Give 5 examples of data that you can collect from day to day life and represent them in tabular form. Answer: Following are the five... View Article

A body cools from 5t to 2t in 5 minutes. The room temperature is t. Assume that Newton’s law of cooling is applicable. The temperature of the body at the end of next 5 minutes will be

A body cools from 5t to 2t in 5 minutes. The room temperature is t. Assume that Newton’s law of cooling is applicable. The temperature of the... View Article