JAMB UTME - Physics - 1979

Which of the following statements defines correctly the efficiency of a machine?

Antwortdetails

An electrical circuit is connected up as shown above, which of the following is correct about the value of current flowing through the 1 ohm resistance?

Antwortdetails

A weight of 1000 grams hangs from a lever 20cm to the fulcrum. At the left is a 500-gram weight 20cm from the fulcrum, and a 200-gram weight x cm away from the fulcrum. What is the value of x that will make the lever balanced?

Antwortdetails

When the vapour of a substance is in equilibrium with its own liquid, it is said to be

Antwortdetails

Two closed vessels contain equal volumes of boiling water and are identical except that one is blackened on the outside while the other is polished. Which of the following is correct?

Antwortdetails

The diagram shows lens arrangement in

Antwortdetails

The heights of the mercury thread in a mercury-in-glass thermometer when in melting ice and then in steam are 3cm and 18cm respectively. At a temperature of 60^oC the height would be

Antwortdetails

If a given mass at constant pressure obeys the relation...volume is proportional to the absolute temperature...the gas is said to obey

Antwortdetails

A man standing between two parallel mirrors in a barber's shop will see the following number of his own image

Antwortdetails

Fig 8 shows a current I flowing in a copper wire situated in a magnetic field existing between the pole-pieces of a horse-shoe magnet.
Which of the following statements is correct?

Antwortdetails

All the heat generated in a 5 ohms resistor by 2A flowing for 30 seconds is used to evaporate 5g of a liquid at its boiling point. Which of the following is the correct value of the specific latent heat of the liquid?

Antwortdetails

A landlord has eight 40W electric light bulbs, four 60W bulbs and two 100W bulb in his house. If he has all the points on for five hours daily and if N.E.P.A. charges 5k per unit, his bill for 30 days is

Antwortdetails

In a resonance tube experiment, which is illustrated above, the velocity of sound in air is 327.68m/s, the frequency of the turning fork used is therefore

Antwortdetails

What are the units of thermal conductivity?

Antwortdetails

A concave lens of focal length 20cm form an image 1/2 the size of the object. The object distance is

Antwortdetails

Which of the following statements is correct? The magnetized state of an iron bar can be destroyed completely by

Antwortdetails

An object is placed 30cm from a concave mirror of focal length 15cm. the linear magnification of the image produced is

Antwortdetails

The bulb of a motorcycle head-lamp is marked 40W, 6V. The resistance of the filament when it is switched on is

Antwortdetails

Which of the following is the correct definition of 'half-life'?

Antwortdetails

A uniform bean HK of length 10m and weighing 200N is supported at both ends as shown above. A man weighing 1000N stands at a point P on the beam. If the reactions at point H an K respectively are 800N and 400N, Then the distance HP is

Antwortdetails

fig 12 shows the velocity time graph of a car which starts from rest and is accelerated uniformly at the rate of 3m sec^-2 for 5 seconds. It attains a velocity which is maintained for a minute, The car is then brought to rest by a uniform retardation after another 3 seconds. calculate the total distance covered

Antwortdetails

In what range of temperature is the expansion of water anomalous?

Antwortdetails

A body is released from rest and allowed to fall freely from a given height under gravity. The kinetic energy at its half-way point is

Antwortdetails

A 500kg car which was initially at rest travelled with an acceleration of 5m sec^-2, its kinetic energy after 4 seconds was

Antwortdetails

On which of the following is the operation of a moving coil galvanometer based?

Antwortdetails

If in a simple pendulum experiment the length of the inextensible string is increased by a factor of four, its period is increased by a factor of

Antwortdetails

It is known that a neutron exists in a light atomic nucleus. Which of the following also exists in the nucleus?

Antwortdetails

Which of the following statements is incorrect? The sensitivity of a galvanometer which incorporates an optical lever arrangement may be increased by providing

Antwortdetails

For the wave motion represented above

The wavelength is given by

Antwortdetails

The density 400cm³ of palm oil was 0.9gcm^-3 before frying. If the density of the oil was 0.6gm^-3 after frying,assuming no loss of oil due to spilling, its new volume was

Antwortdetails

Which of the following statements is true? The frequency of a vibrating string is

Antwortdetails

An air column 10cm in length is trapped into the sea end of a capillary tube by a 15cm column of mercury with the tube held vertically as shown above. On inverting the tube the air column becomes 15cm long. The atmospheric pressure during the experiment is

Antwortdetails

An air bubble rises from the bottom to the top of a water dam which is 40m deep. The volume of the bubble just below the surface is 2.5cm³. Find its volume at the bottom of the dam, if atmospheric pressure is equivalent to 10m water

Antwortdetails

Which of the following electromagnetic waves has the shortest wavelength?

Antwortdetails

In a given circuit, the cell P has an emf 1.5V and an unknown internal resistance while cell Q has an emf 2.0V and an internal resistance of 1 ohm if the ammeter reads 50m A, Then r is equal to

Antwortdetails

Which of the following types of waves cannot travel through a vacuum?

Antwortdetails

If the wavelength of a wave travelling with a velocity of 360ms^-1 is 60cm, the period of the wave is

Antwortdetails

Consider a thick glass tumbler and a thin glass tumbler which are made of the same kind of glass. Some hot liquid is poured into them. Which of the following statements is correct?

Antwortdetails

Which of the following statements is correct? Silvered walls of a vacuum flask are used to prevent

Antwortdetails

Radio carrier waves are generated by causing electrons to oscillate rapidly in

Antwortdetails

A capacitor and a resistor are connected in series with each other and in series with an accumulator of negligible internal resistance. The potential across the terminals of the capacitor is

Antwortdetails

An electric cell has an internal resistance of 2 ohms. A current of 0.5A is found to flow when a resistor of 5 ohms resistance is connected across it. What is the electromotive force of the cell?

Antwortdetails

Which of the following statements about radioactivity are true? i. alpha particle is positively charged ii. Beta particle is negatively charged iii. Gamma ray is neutral iv. Beta particle has the same mass as helium atom v. Gamma ray is charged

Antwortdetails

The speed of light in air is 3 x 10⁸ms^-1. If the refractive index of light from air-to-water is \(\frac{4}{3}\), then which of the following is the correct value of the speed of light in water?

Antwortdetails

Which of the following statements is correct? The reading of pressure on a mercury barometer is independent of

Antwortdetails

fig 10 shows a see-saw which is perfectly in balance, the weighs of the people sitting on it are 50kg, xkg and 15kg as shown, the sit at distances of 1.5, 1.5 and 2m from the pivot respectively. The vale of X is

Antwortdetails

The temperature at which the water vapour present in the air saturates the air and begins to condense is known as

Antwortdetails

In an electrolysis experiment, a cathode of mass 5g is found o weigh 5.01g after a current of 5A flows for 50 seconds. What is the electrochemical equivalent of the deposited substance?

Antwortdetails