Question Discussion & Solution

The correct answer is Constellation.

• Ursa Major constellation lies in the northern sky. Its name means “the great bear,” or “the larger bear” in Latin.
• Ursa Major is the largest northern constellation and third largest constellation in the sky.
  • Its brightest stars form the Big Dipper asterism, one of the most recognizable shapes in the sky, also known as the Plough.
• Ursa Major contains seven Messier objects. It also contains 13 stars with confirmed planets.

Important Points

• The biggest known galaxy is IC 1101, which is 50 times the Milky Way's size and about 2,000 times more massive.
  • It is about 5.5 million light-years across.
• Our Sun (a star) and all the planets around it are part of a galaxy known as the Milky Way Galaxy.
  • A galaxy is a large group of stars, gas, and dust bound together by gravity. The Milky Way is made up of about 90% dark matter, the matter which cannot be seen, and about 10% “luminous matter”, or matter that we can see with our eyes.
  • The solar system lies about 30,000 light-years from the galactic centre.

Additional Information

• Sirius, also known as the Dog Star or Sirius A, is the brightest star in Earth's night sky.
• The name means "glowing" in Greek.

The mirror image of this image is:

Hence, option (2) is the correct answer.

The correct answer is 4°C.

• Freezing of Water:
  • As water freezes, cold water (or ice formed) comes on the surface and warm water goes down.
  • Since the freezing temperature of the water is 0ºC or 273 K.
  • So water at the bottom should be at a higher temperature.
  • Water density at 4ºC is more than the density of water at 0ºC, hence the correct option is 4ºC.

​Key Points

• Reason of low temperature at bottom of the top layer:
  • This is due to the process of convection.
  • When the temperature of the water at the top layer reaches the freezing point, it is converted to ice.
  • But ice is lighter than water, so it will not sink to the bottom.
  • So there will be ice on the top surface and water would remain at the bottom of the lake. 

Hence, “8” will come in the place of question mark. 

Void pointer: It is a specific pointer type – void * – a pointer that points to some data location in storage, which doesn’t have any specific type. Void refers to the type.

• void pointers cannot be dereferenced. It can however be done using typecasting the void pointer
• Pointer arithmetic is not possible on pointers of void due to lack of concrete value and thus size

Other Important Points

Dangling pointer: A pointer pointing to a memory location that has been deleted (or freed) is called dangling pointer.   

Uninitialized pointer : An uninitialized pointer stores an undefined value. A null pointer stores a defined value, but one that is defined by the environment to not be a valid address for any member or object.

NULL Pointer : NULL Pointer is a pointer which is pointing to nothing. In case, if we don’t have address to be assigned to a pointer