For a short sighted person, light rays from a point on a very distant object is focused
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1990
What must be the distance between an object and a converging lens of focal length 20cm to produce an erect image two times the object height?
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1990
A boy looks at the image of an object in a plane mirror. He observes two images, a main bright one and the other faint. The observed images result from
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1990
An object which is 3cm high is placed vertically 10cm in front of a concave mirror. If this object produces an image 40cm from the mirror, the height of the image is
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1990
Which of the following statements are true of an insulated charged body carrying positive charge? i. it contains excess positive charges. ii. it creates an electric field. iii. it possesses potential energy. iv. it carri…
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1990
One of the properties of the earth's magnetic field is that the
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1990
A sonometer wire of length 100cm under a tension of 10N, has a frequency of 250Hz. Keeping the length of the wire constant, the tension is adjusted to produce a new frequency of 350Hz. The new tension is
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1990
An organic pipe closed at one end is 80cm long. Determine the frequency of the fundamental note assuming that the speed of sound in air is 340ms-1
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1990
In a resonance tube experiment, the effective length of the air column for the first resonance is 20cm when set into vibration by a tuning fork of frequency 480Hz. Neglecting and effect, the velocity of sound in air is
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1990
Which of the following is an essential physical property of the wires used for making fuses?
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1990
The total energy required to send a unit positive charge round a complete electrical circuit is the
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1990
When a known standard resistor of 2\(\Omega\) is connected to the 0.0cm end of a meter bridge, the balance point is found to be at 55.0cm. What is the value of the unknown resistor?
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1990
Three cells each of e.m.f. 1.5v and an internal resistance of 1.0\(\Omega\) are connected in parallel across a load resistance of 2.67\(\Omega\). Calculate the current in the load?
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1990
Which of the following is a vector?
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1990
The number of neutrons contained in the nucleus \(^{238}_{92}U\) is
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1990
A 0 - 10mA galvanometer with a coil resistance of 30\(\Omega\) can be converted to a 0 - 10A ammeter by using
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1990
A lamp is rated 240V, 60W. The resistance of the filament is
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1990
Electrical power is transmitted at a high voltage rather than low voltage because the amount of energy loss is reduced due to
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1990
Which of the following is most suitable for protecting the circuit of 2000W electric iron connected to a 250V mains?