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വായുവിൽ നിന്നും ജലത്തിന്റെ ഉപരിതലത്തിൽ വന്നു പതിച്ച പ്രകാശം പ്രതിപതനം സംഭവിക്കുമ്പോൾ പൂർണമായി ധ്രുവീകരിക്കുന്ന കോൺ കണക്കാക്കുക
Which of the following materials is preferably used in making heating elements of electrical heating devices?
Two resistors of 4Ω each are connected in parallels to a 5 V battery source. The total current in the circuit is?
An object placed 30 cm from a concave lens forms a virtual erect image at a distance of 10 cm from the lens. The magnification produced by the lens is?
At which position on principal axis does a concave mirror forms a highly diminished, real and inverted image of an object?
A wire of a given material has length '1' and resistance 'R'. Another wire of the same material having nine times the length and the same area of cross section will have a resistance equal to?
A spherical mirror converges a beam of light, at a given point on the principal axis. Which of the following statement(s) about the mirror is are true?
- (a) The mirror used in concave
- (b) The mirror has positive focal length
- (c) The point of convergence is the principal focus of the mirror
A convex lens produces a magnification of-3 for an object placed at 1.5 m from the leas. Find the image distance (with correct sign).
An electric heater is rated 2200 W at 220 V. The minimum rating of the fuse wire to be connected to the device is?
An electric heater rated 1000 W and an electric geyser rated 2000 W are med for 4 hours daily. The energy consumed in 10 days (in kWh) is?
Which of the following is/are useful effort(s) for sustainability of resources?
- a. Switching off unnecessary lights and fans
- b. Using lift instead of stairs
- c. Repairing leaking taps for conserving water
- d. Using empty containers to store things
- e. Going to school by your own car instead of cycling
A magnet, when moved near a coil, produces an induced potential difference in the coil, What happens when we increase the speed of the magnet near the coil?
A concave mirror having focal length of magnitude 20 cm forms a real image at a distance of 60 cm from it. The object distance (in cm) is?
For a ray of light undergoing refraction through a triangular glass prism, the angle of deviation is the angle between?
A convex lens having power 5 D is placed in contact with a concave lens having power-3 D. The focal length of the combination will be?
Which of the following statements is/are true for a DC motor?
- (1) The function of the split rings is to reverse the flow of current.
- (ii) Maximum force is experienced by arms of the coil aligned parallel to the magnetic field
- (iii) Reversing current after every half rotation leads to continuous rotation of coil
Which of the following devices is/are based on heating effect of electric current?
- (i) Incandescent lamp
- (ii) Electric geyser
- (iii) Electric generator
The direction of a magnetic field due to a straight current carrying conductor can be determined using?
Q.2 Ramesh wants to choose a material for making filament of a bulb. The chosen material should possess which of the following properties?
- (1) Low melting point
- (ii) Ability to glow at high temperatures
- (iii) High resistance
The ratio of the field due to a current-carrying circular coil of n turns to the field due to a single circular loop of the same radius carrying the same current is _________?
To investigate the conduction of electric current, Ravi performed an experiment. He took different aqueous solutions or liquids (as electrolyte) and tried to pass electricity and connected the circuit with a bulb. In the presence of which of the following, will the bulb NOT glow?
A concave mirror forms a real, inverted and same-sized image of an object. Where is the object placed?
The speed of light in two transparent media A and B are 2×10^8 m/sec and 2.25 × 10^8 m/sec. The refractive index of medium A with respect to medium B is equal to?
The refractive index of a given transparent medium is 1.5. What will be the speed of light in that medium?
The magnification 'm' produced by a convex lens when the object is placed at a distance 2f from the lens is given by?
A potential difference of 5 V when applied across a conductor produces a current of 2.5 mA. (inf) is The resistance of the conductor (in Ω) is?
Which of the following line(s) act as a normal to a spherical mirror?
- (i) Line joining the pole and centre of curvature
- (ii) Line joining the centre of curvature and point of incidence
- (iii) Line joining focus and point of incidence
The property/properties that must be possessed by a material to be chosen for making heating element of heating devices is/are:
- (i) high melting point
- (ii) high resistivity
- (iii) low resistance
Which of the following rules is used to determine the force on a current carrying conductor kept inside a magnetic field?
The magnetic field produced due to a circular coil carrying a current having six turns will be how many times that of the field produced due to a single circular loop carrying the same current?
A spherical mirror forms an erect and diminished image. Identify the correct statements about the spherical mirror.
- (A) The mirror is concave.
- (B) The mirror forms a virtual image.
- (C) The mirror has positive focal length.
A magnet, when moved near a coil, produces an induced current. Which of the following method(s) can be used to increase the magnitude of the induced current?
- (1) Increasing the number of turm in the coil
- (2) Increasing the speed of the magnet
- (3) Increasing the resistivity of the wire of the coil