An ammeter connected to an a.c circuit records 5.5. The peak current in the circuit is
- A. 7.8A
- B. 7.1A
- C. 3.8A
- D. 3.5A
An inductor of inductance 1.0H is connected in series with a capacitor of capacitance 2.0\(\mu F\) in an a.c. circuit. to resonate
- A. 112.5Hz
- B. 225.0Hz
- C. 323.5Hz
- D. 707.1Hz
If the direction of the curent in a straight wire is reversed, the magnetic field
- A. remains the same
- B. becomes parallel to the wire
- C. ceases to exist
- D. is oppositely directed
A battery of e.m.f. 12.0V and internal resistance0.5\(\Omega\) is connected to 1.5\(\Omega\) and 4.0\(\Omega\) series resistor. Calculate the terminal voltage of the battery.
- A. 13.0V
- B. 11.0V
- C. 3.0V
- D. 1.0V
A wire of resistivity 4.40 x 10-5\(\Omega\) cm has a cross sectional area of 7.50 x 10-4 cm2. Calculate the length of the wire that will be required to make a 4.0\(\Omega\) resistor
- A. 82.50 cm
- B. 68.18cm
- C. 15.90cm
- D. 11.95cm
A cell of e.m.f. 1.5V is connected in series with a resistor of resistance 3.0\(\Omega\). A voltmeter connected across the cell registers 0.9V. Calculate the internal resistance of the cell
- A. 2.0\(\Omega\).
- B. 3.0\(\Omega\).
- C. 5.0\(\Omega\).
- D. 6.0\(\Omega\).
A resistor of resistance R is connected to a battery of negligible internal resistance. If a siilar resistor is connected in series with it the
- A. effective resistance of the circuit is halved
- B. total power dissipated is doubled
- C. total current in the circuit is halved
- D. terminal voltage is halved
An isolated metal sphere of radius R, carrying an electric charge Q, is situated in the medium of relative permitivity, Er. A test charge is placed at a point p, distance r from the surface of the sphere. Let Eo represent the permitivity of free space. The magnitude of the electric field intensity at P is given by the expression
- A. \(\frac{Q}{4 \pi E_o E_r r^2}\)
- B. \(\frac{Q}{4 \pi E_o E_r(R + r)^2}\)
- C. \(\frac{Q}{4 \pi E_o E_r(R - r)^2}\)
- D. \(\frac{Q}{4 \pi E_o E_rR^2}\)
An isolated metal sphere of radius R, carrying an electric charge Q, is situated in the medium of relative permitivity, Er. A test charge is placed at a point p, distance r from the surface of the sphere. Let Eo represent the permitivity of free space. The electric potential at p is given by the expression
- A. \(\frac{Q}{4 \pi E_o E_r}\)
- B. \(\frac{Q}{4 \pi E_o E_r (R +r)}\)
- C. \(\frac{Q}{4 \pi E_o E_r(R - r)}\)
- D. \(\frac{Q}{4 \pi E_o E_rR}\)
When a conductor mounted on an insulating stand is charged and left for sometime, the conductor eventually loses all its charges. This is because the
- A. electric charges evaporate from the surface of the conductor
- B. charges are connected to earth
- C. charges on the conductor are neutralized by opposite charges from the surrounding air
- D. charges ionize the surrounding air
A satellite in circular motion around the earth does not have
- A. a gravitational force acting on it
- B. a uniform velocity
- C. an acceleration
- D. a centripetal force acting on it
Sound interference is necessary to produce the phenomenon of
- A. beats
- B. doppler effect
- C. acoustic resonance
- D. echo
Which of the following is not a part of the electro-magnetic spectrum?
- A. x-rays
- B. microwaves
- C. infrared radiation
- D. alpha rays
Which of the following characteristics of light determines its colour?
- A. velocity
- B. wavelength
- C. amplitude
- D. intensity
A thin lens is placed 50cm from an illustrated object. The image produced has linear magnification of \(\frac{1}{4}\). Calculate the power of the lens in dioptres
- A. 2.5D
- B. 5.0D
- C. 10.0D
- D. 25.0D
A concave mirror forms a magnified and errect image only when the object is placed
- A. at the centre of curvature
- B. at the focus
- C. between the focus and the pole of the mirror
- D. beyound the radius of curvature
The angle of incidence of a ray of light on a plane mirror is 55o. Determine the angle between the reflected ray and the mirror
- A. 35o
- B. 45o
- C. 55o
- D. 110o
Light travelling through a small pinhole usually does not make a shadow with a distinct sharp edge because of
- A. diffraction
- B. inteference
- C. reflection
- D. refraction
Which of the following waves is not transverse
- A. light waves
- B. sound waves
- C. sea waves
- D. radio waves
A boat is rocked by waves of speed 30ms-1 whose successive crest are 10m apart. Calculate the rate at which the boat recieves the waves
- A. 30s-1
- B. 10s-1
- C. 3s-1
- D. 1s-1
The maximum displacement of a vibrating tunning fork is its
- A. amplitude
- B. frequency
- C. period
- D. wavelength