Fusion is not usually used for generating electric power because
- A. no energy is released when fusion takes place
- B. very high temperatures are required to initiate fusion reaction
- C. the raw materials needed is not easily available
- D. heavy nuclei are involved
A radioactive substance of mass 768g has a half life of 3 years. After how many years does this substance leave only 6g undecayed?
- A. 21
- B. 18
- C. 15
- D. 12
A 500kV is applied across an X-ray tube. Calculate the maximum velocity of the electrons produced [Me = 9.1 x 10-31kg, e = 1.6 x 10-19C]
- A. 4.2 x 108ms-1
- B. 1.9 x 108ms-1
- C. 4.2 x 105ms-1
- D. 1.8 x 105ms-1
The breaking up of an atomic nucleus into the fragment of nearly equal size is known as
- A. nuclear fusion
- B. nuclear fission
- C. thermonuclear reaction
- D. natural radioactivity
The force experienced by a current-carrying conductor move in a magnetic field is employed in the working of the i. moving coil ammeter ii. electric bell iii. electric motor. Which of the statements above are correct?
- A. i and ii only
- B. ii and iii only
- C. i and iii only
- D. i, ii and iii
Which of the following statements about a bar magnet is correct?
- A. iron fillings cling uniformly along the length of a bar magnet
- B. the magnetic properties are more pronounced at the middle of a magnet
- C. it is impossible to have the same poles at the end of a magnet
- D. the magnetic properties are more pronounced at points near the end of the bar
An electric lamp rated 120W is used on a 240Vrms, calculate the resistance of its filament
- A. 480\(\Omega\)
- B. 360\(\Omega\)
- C. 60\(\Omega\)
- D. 2\(\Omega\)
a cell of e.m.f. 1.5V and internal resistance 1.0\(\Omega\) is connected to two resistor of resistance 2.0\(\Omega\) and 3.0\(\Omega\) in series. Calculate the current through the resistors
- A. 0.25A
- B. 0.30A
- C. 0.35A
- D. 0.50A
The equivalent capacitance of a 3\(\mu F\) capacitor and a 6\(\mu F\) capacitor connected in parallel is
- A. 2.0\(\mu F\)
- B. 3.0\(\mu F\)
- C. 4.5\(\mu F\)
- D. 9.0\(\mu F\)
Which of the following factors does not affect the capacitance of a parallel plate capacitor?
- A. area of the plates
- B. nature of the surface of the plates
- C. distance of separation between the plates
- D. nature of the insulating material between the plates
An electron of mass m and charge \(\Box\) enters a uniform electric field between two metal plates P and q separated by a distance d. P is maintained at a potential V while Q is earthed. Determine an expression for the magnitude of the acceleration of electron through the field
- A. \(\frac{eV}{md}\)
- B. \(\frac{d}{meV}\)
- C. \(\frac{md}{eV}\)
- D. \(\frac{e}{Vmd}\)
The acceleration due o gravity may be defined as the force
- A. of attraction of the sun and on the earth
- B. with which the earth revolves around the sun
- C. with which the earth attracts one kilo-gram mass
- D. of the moon on the earth
Which of the following actions is necessary in order to tune a string to produce a note of an octave higher than its fundamental?
- A. doucling the length of the string
- B. reducing the tension by half
- C. reducing the mass per unit length
- D. increasing the tension four times
In which of the following media would sound wave travel fastest?
- A. wood
- B. water
- C. iron
- D. mercury
A travelling microscope is focused on a mark on a table. If a glass block of thickness 18.0cm is placed on the mark by how many centimeters will the microscope be moved upwards so as to focus the mark once again? [refractive index of glass = 1.5]
- A. 27cm
- B. 24cm
- C. 9cm
- D. 6cm
Which of the following distances is usually adjustable in the camera? The distance between the
- A. lens and the film
- B. diaphragm and the shutter
- C. shutter and the film
- D. diaphragm and the film
A ray from a fixed object is incident on a plane mirror at an angle of 20o. If the mirror is rotated through 30o by how many degree would the reflected ray rotate?
- A. 60o
- B. 50o
- C. 40o
- D. 30o
The distance between the successive crests of a wave travelling at 20ms\(^{-1}\) is 25cm. Calculate the frequency of the wave
- A. 0.8Hz
- B. 5.0Hz
- C. 50.0Hz
- D. 80.0hz
Which of the following observations cannot be explained using the rectilinear propagation of light?
- A. production of images by a pinhole camera
- B. production of real images of objects by lenses
- C. formation of an annular eclipse
- D. diffraction patterns of light
The eclipse of the moon occurs when the
- A. moon comes exactly between the earth and the sun
- B. earth comes exactly between the moon and the sun
- C. sun comes exactly between the earth and the moon
- D. moon reflects all the rays from the sun onto the earth
a note of frequency 2000Hz has a velocity of 400 ms-1. calculate the wavelength of the note
- A. 5.0m
- B. 2.0m
- C. 0.5m
- D. 0.2m